Treasury Stock (Details) (USD $)	3 Months Ended		9 Months Ended		0 Months Ended			1 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Apr. 30, 2014 Senior Notes Due 2019 [Member]	Apr. 30, 2014 Privately Negotiated Transaction [Member]	Apr. 30, 2014 Purchase From Accelerated Share Repurchase [Member]	Oct. 31, 2014 Subsequent Event [Member] Purchase From Accelerated Share Repurchase [Member]
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount			$ 5,400,000,000
Amount used to repurchase stock			1,600,986,000	156,334,000		101,000,000
Available to repurchase common stock			328,300,000
Amount expended on share repurchases in open market transactions	99,900,000	55,300,000	99,900,000	156,300,000
Stock repurchased during period, value					1,500,000,000		1,400,000,000
Stock repurchased during the period, shares					1,700,000		19,200,000	2,630,333
Stock repurchased during period, percent of all shares included in agreement							80.00%
Number of shares repurchased	1,434,400	764,800	1,434,400	2,240,050
Average per share price on share repurchases in open market transactions (in dollars per share)	$ 69.71	$ 72.30	$ 69.71	$ 69.79
Number of shares withheld to satisfy minimum tax withholding obligations	75,797	43,035	470,567	389,369
Payment for tax withholding related to vested stock units	$ 4,900,000	$ 2,900,000	$ 27,800,000	$ 27,700,000