The deal in cash and stock will give Verizon full access to the profits from the United States' largest mobile operator, handing it fresh firepower to invest in its mobile network and fend off challengers in a tough market that is fast becoming even more competitive.
For the British group, the accord will allow it to return 71 percent of the net proceeds - or $84 billion including all of the stock - to shareholders while also ramping up investment in its networks to set itself apart from rivals.
The deal, in which Verizon will buy Vodafone's 45 percent stake in Verizon Wireless, is the defining event in the careers of Vittorio Colao and Lowell McAdam, the chief executives of Vodafone and Verizon, respectively. They had succeeded in rebuilding relations between the two sides, long strained by clashes about the Wireless dividend and who would eventually seize full ownership.
McAdam told Reuters in an interview that the two men had initially discussed the possibility of combining Verizon and Vodafone before deciding that the stake sale made more sense for both companies.
He said the companies realized they were close to a deal after they spent the morning together in a hotel in San Francisco, chatting while on the exercise bike in the gym and later over breakfast.
The code name assigned to the deal was Project River. "We were Hudson and they were the Thames," he said, referring to rivers in New York and London.
Under the terms, Vodafone will get $58.9 billion in cash, $60.2 billion in Verizon stock, and an additional $11 billion from smaller transactions in a deal that is due to close in the first quarter of next year.
The deal will become the third largest announced deal in the world after Vodafone's $203 billion takeover of Germany's Mannesmann in 1999 and AOL's $181 billion acquisition of Time Warner the following year. Verizon has also managed to raise one of the largest ever financing packages at $60 billion.
"We think we have a balanced approach here," Colao told reporters, adding that he was "super committed" to the next chapter of the company. "We are reducing our debt level which will enable the company to be very robust and take opportunities if they arise."
McAdam said simply that the time was right to buy.
"I think there's going to be a burst of rocket fuel in the Verizon engine as a result of this transaction," the executive told Reuters. He said it was a self-funding transaction because Verizon's earnings per share will immediately increase by 10 percent, excluding one-time items.
However, the addition of a massive new debt load on Verizon's books, may tie the company's hands on major investments for some time as paying down its debt should be a priority, analysts said.
"It probably, in the short term at least, limits Verizon's ability to do other large transactions," said Macquarie analyst Kevin Smithen. He also worried that Verizon paid too high a price at a time when growth is slowing in the U.S. wireless industry and smaller rivals are competing aggressively on price.
In fact, Verizon is not interested in entering the Canadian wireless market, a Verizon spokesman said confirming McAdam's statements made earlier during an interview with Bloomberg.
Moody's Investors Service downgraded its rating on Verizon after the news to reflect an increase in debt leverage from the addition of about $67 billion of new debt which the credit ratings agency said will more than double Verizon's debt load to $116 billion.
The final agreement follows years of speculation as to whether Vodafone, the world's second largest mobile operator, would leave or be forced out of the highly successful business.
Talks between the two sides picked up in earnest over the summer as Verizon grew concerned that its window of opportunity was closing, with interest rates due to rise and its own stock price declining. That prompted Verizon to raise the offer from the $100 billion it had initially floated to close to Vodafone's asking price of $130-$135 billion, sources told Reuters.
For Colao, the timing was also fortuitous as Europe is showing tentative signs of recovery and the U.S. looks headed for tougher competition after Japan's SoftBank Corp, a scrappy mobile competitor at home, took control of Sprint Corp the No. 3 U.S. wireless provider.
"Verizon finally got serious about paying a full price and then there was a lot of good will to work it out," one person familiar with the deal said.
"You have a window in the market where you can lock in a lot of funding at historically low interest rates. Part of the concern was that the window may not be there (forever)."
Both boards unanimously approved the sale.
Since Verizon already had operational control of the wireless company, the deal is not expected to affect its 100 million customers, but its additional financial firepower once it has paid down some of the hefty debt load could help it compete more aggressively against its rivals.
However, although Verizon had long said its control of Verizon Wireless was not restricted by Vodafone's ownership, Forrester analyst Charles Golvin said that the absence of a partner could give Verizon more flexibility in marketing its wireline Internet and television services and its wireless offerings together.
"There was always influence even though Verizon might say they had full decision making control," Golvin said.
While Vodafone will lose its best asset, it will get a war chest to reward shareholders, pay down debt and bolster its European operations, which are under pressure from recession and tough regulation.
It said it planned to launch a new investment phase dubbed "Project Spring," to improve its mobile and broadband networks across its networks in Europe and emerging markets such as India and South Africa.
After making one of the largest shareholder returns in history, Vodafone will be left with a $30 billion cash pile. Some 6 billion pounds ($9 billion) will go to the Project Spring network investment programme and the rest will be used to pay down debt, bringing down leverage to one times forward operating profit (EBITDA).
Vodafone spent 6.3 billion pounds on network investment in its last fiscal year, so the further 6 billion pounds spread over three years for Project Spring does represent a significant new effort for the group.
Vodafone is not earmarking any of the cash for acquisitions, although Colao said that the group could always borrow later if attractive deal opportunities crop up that would create value for shareholders. Bankers and analysts had expected Vodafone to consider acquisitions in fixed-line assets in Europe after recent deals in Britain and Germany.
Both groups said they would now be in a position to increase their dividend. Vodafone will be left with a U.S. tax liability of around $5 billion, which was lower than some analysts expected.
This is because Vodafone does not have to pay any tax on the gain in the UK or in the Netherlands, where the Vodafone unit which owns the unit being sold is based.
These countries do not levy tax on profits companies make from selling substantial stakes - usually over 10 percent - in other companies. The tax due in the United States is limited because the seller is a non-U.S. entity.
Lead advisers for Verizon were boutique M&A firm Guggenheim Partners, Morgan Stanley, and Paul Taubman, a former banker at Morgan Stanley.
Barclays and Bank of America Merrill Lynch acted as financial advisors to Verizon, and will also underwrite the $61 billion in financing for the bid alongside JPMorgan and Morgan Stanley. Goldman Sachs and UBS advised Vodafone.
($1 = 0.6425 British pounds)
(Additional reporting by Soyoung Kim, Michelle Sierra, Sinead Carew, Sophie Sassard, Leila Abboud, Chris Vellacott, Neil Maidment, Paul Sandle, Anjuli Davies, Ilaina Jonas and Tom Bergin; editing by Will Waterman, Giles Elgood, G Crosse and Bernard Orr)
By Kate Holton and Sinead Carew