Net Income per Share (Computations Of Basic And Diluted Net Income Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Net income	$ 172	$ 167	$ 368	$ 366
Weighted-average shares, basic for Class A and Class B	424,169	430,216	426,055	430,050
Effect of dilutive securities	2,628	3,983	2,717	4,168
Weighted-average shares, diluted for Class A and Class B	426,797	434,199	428,772	434,218
Net income per weighted-average share, basic for Class A and Class B	$ 0.41	$ 0.39	$ 0.86	$ 0.85
Net income per weighted-average share, diluted for Class A and Class B	$ 0.40	$ 0.38	$ 0.86	$ 0.84