Acquisitions (Details 2) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009
Pro Forma Impact of the Acquisition
Revenue	$ 15,903	$ 13,301
Net income	$ 828	$ 345
Basic net income per share	$ 1.92	$ 0.81
Diluted net income per share	$ 1.91	$ 0.80