Stockholders' Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Stockholders' Equity Note [Abstract]
Class B common stock repurchased under repurchase program (shares)	7.6
Value of shares repurchased	$ 500
Average price per share repurchased (in dollars per share)	$ 65.97
Remaining authorization under share repurchase program	$ 3,610
Dividends [Abstract]
Dividends per common share (in dollars per share)	$ 0.18	$ 0.15
Dividends recorded on common stock	$ 75	$ 69
Tax provision on net actuarial gain (loss) and prior service costs related to pension and other postretirement benefit plans	8	6
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss)	(753)	(759)	$ (767)	$ (770)
Other comprehensive income (loss) before reclassifications	2	1
Reclassifications to net earnings (loss)	12	10
Net other comprehensive income (loss)	14	11
Cumulative Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss)	153	153	151	152
Other comprehensive income (loss) before reclassifications	2	1
Reclassifications to net earnings (loss)	0	0
Net other comprehensive income (loss)	2	1
Net Actuarial Gain (Loss) and Prior Service Cost [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss)	(906)	(912)	$ (918)	$ (922)
Other comprehensive income (loss) before reclassifications	0	0
Reclassifications to net earnings (loss)	12	10
Net other comprehensive income (loss)	$ 12	$ 10