Shareholders' Equity (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Changes in Shareholders' Equity [Roll Forward]      
Beginning balance $ 1,385    
Net income 583 432  
Other comprehensive income, net of tax (339) (87)  
Ending balance 739    
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax 2,805   2,453
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax 1,051   1,064
Common Stock [Member]      
Changes in Shareholders' Equity [Roll Forward]      
Beginning balance     1,466
Ending balance 1,466   1,466
Additional Paid-In Capital [Member]      
Changes in Shareholders' Equity [Roll Forward]      
Beginning balance 1,236    
Stock-based compensation expense 32    
Shares issued for stock options 32    
Stock issued for restricted stock awards (29)    
Other 1    
Ending balance 1,272    
Unearned Compensation [Member]      
Changes in Shareholders' Equity [Roll Forward]      
Beginning balance (20)    
Other 7    
Ending balance (13)    
Treasury Stock [Member]      
Changes in Shareholders' Equity [Roll Forward]      
Beginning balance (16,862)    
Shares issued for stock options 85    
Stock issued for restricted stock awards 29    
Treasury stock acquired (374)    
Ending balance (17,122)    
Retained Earnings [Member]      
Changes in Shareholders' Equity [Roll Forward]      
Beginning balance 18,832    
Net income 542    
Dividends (670)    
Ending balance 18,704    
Accumulated Other Comprehensive Income (Loss) [Member]      
Changes in Shareholders' Equity [Roll Forward]      
Beginning balance (3,507)    
Other comprehensive income, net of tax (340)    
Ending balance (3,847)    
Noncontrolling Interests [Member]      
Changes in Shareholders' Equity [Roll Forward]      
Beginning balance 240    
Net income 41    
Other comprehensive income, net of tax 1    
Dividends (3)    
Ending balance $ 279