v3.6.0.2
Equity (Changes in Common Stock) (Details) - shares
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Class A Common Stock [Member]      
Increase (Decrease) in Stockholders' Equity [Roll Forward]      
Common stock, shares outstanding at beginning of period (in shares) 2,432,953,988 2,131,000,000 2,138,000,000
Stock compensation plans (in shares) 11,000,000 12,000,000 13,000,000
Repurchases and retirements of common stock (in shares) (81,000,000) (62,000,000) (22,000,000)
Employee stock purchase plan (in shares) 3,000,000 2,000,000 2,000,000
Reclassification of Class A Special common stock (in shares)   346,000,000  
Other (in shares)   4,000,000  
Common stock, shares outstanding at end of period (in shares) 2,366,357,318 2,432,953,988 2,131,000,000
Class A Special Common Stock [Member]      
Increase (Decrease) in Stockholders' Equity [Roll Forward]      
Common stock, shares outstanding at beginning of period (in shares) 0 400,000,000 459,000,000
Stock compensation plans (in shares) 0 0 0
Repurchases and retirements of common stock (in shares) 0 (54,000,000) (59,000,000)
Employee stock purchase plan (in shares) 0 0 0
Reclassification of Class A Special common stock (in shares)   (346,000,000)  
Other (in shares)   0  
Common stock, shares outstanding at end of period (in shares) 0 0 400,000,000
Class B Common Stock [Member]      
Increase (Decrease) in Stockholders' Equity [Roll Forward]      
Common stock, shares outstanding at beginning of period (in shares) 9,444,375 9,000,000 9,000,000
Stock compensation plans (in shares) 0 0 0
Repurchases and retirements of common stock (in shares) 0 0 0
Employee stock purchase plan (in shares) 0 0 0
Reclassification of Class A Special common stock (in shares)   0  
Other (in shares)   0  
Common stock, shares outstanding at end of period (in shares) 9,444,375 9,444,375 9,000,000