Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Shareholders' net income	$ 588		$ 573	$ 1,121	$ 1,101
Shares:
Weighted average	255,730,000		265,377,000	256,215,000	267,665,000
Common stock equivalents	4,367,000		4,544,000	4,453,000	4,516,000
Total shares	260,097,000		269,921,000	260,668,000	272,181,000
EPS, basic	$ 2.30		$ 2.16	$ 4.38	$ 4.11
EPS, effect of dilution	(0.04)		(0.04)	(0.08)	(0.06)
EPS, diluted	$ 2.26		$ 2.12	$ 4.30	$ 4.05
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common shares held in Treasury	38,694,585		101,424,330	38,694,585	101,424,330
Shares of treasury stock retired		70,000,000
Employee Stock Option [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive options	0		2,000,000	700,000	2,000,000