Treasury Stock (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount	$ 5,400,000,000
Available to repurchase common stock	429,300,000
Amount expended on share repurchases in open market transactions	0	61,400,000
Number of shares repurchased		860,500
Average per share price on share repurchases in open market transactions		$ 71.31
Number of shares withheld to satisfy minimum tax withholding obligations	368,310	322,538
Payment For Tax Withholding Related To Vested And Released Restricted Stock Units	$ 21,200,000	$ 23,200,000