Earnings Per Share (Details) (USD $)
In Millions, except Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Mar. 31, 2014
Earnings Per Share [Abstract]      
Shareholders' net income $ 533   $ 528
Shares:      
Weighted average 256,707,000   269,979,000
Common stock equivalents 4,539,000   4,488,000
Total shares 261,246,000   274,467,000
EPS, basic $ 2.08   $ 1.96
EPS, effect of dilution $ (0.04)   $ (0.04)
EPS, diluted $ 2.04   $ 1.92
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]      
Common shares held in Treasury 38,421,636   97,428,469
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 1,400,000   0