Acquisitions, Goodwill, and Acquired Intangible Assets Goodwill (Details) $ in Millions		6 Months Ended
		Jun. 30, 2015 USD ($)
Goodwill [Line Items]
Goodwill - January 1, 2015		$ 3,319
New acquisitions		218
Other adjustments	[1]	(14)
Goodwill - June 30, 2015		3,523
North America
Goodwill [Line Items]
Goodwill - January 1, 2015		1,978
New acquisitions		41
Other adjustments	[1]	(2)
Goodwill - June 30, 2015		2,017
International
Goodwill [Line Items]
Goodwill - January 1, 2015		735
New acquisitions		17
Other adjustments	[1]	(15)
Goodwill - June 30, 2015		737
AWS
Goodwill [Line Items]
Goodwill - January 1, 2015		606
New acquisitions		160
Other adjustments	[1]	3
Goodwill - June 30, 2015		$ 769

[1] Primarily includes changes in foreign exchange rates.