Consolidated Statements Of Stockholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Capital In Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Balances at Dec. 31, 2014	$ 9,646	$ 33	$ 2,330	$ 9,916	$ 223	$ (2,856)
Balances (in shares) at Dec. 31, 2014		197,952
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,276			1,276
Other comprehensive loss	(165)				(165)
Common stock repurchases	(385)		100			(485)
Dividends and dividend equivalents	(175)			(175)
Stock-based compensation	109		109
Restricted stock unit vesting	0		(49)			49
Restricted stock unit vesting (in shares)		159
Stock option exercises	23		23
Stock option exercises (in shares)		261
Stock option and restricted stock tax benefit	17		17
Balances at Dec. 31, 2015	10,346	$ 33	2,530	11,017	58	(3,292)
Balances (in shares) at Dec. 31, 2015		198,372
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	614			614
Other comprehensive loss	(124)				(124)
Common stock repurchases	(104)					(104)
Dividends and dividend equivalents	(177)			(177)
Stock-based compensation	115		115
Restricted stock unit vesting	0		(98)			98
Restricted stock unit vesting (in shares)		13
Stock option exercises	13		13
Stock option exercises (in shares)		110
Stock option and restricted stock tax benefit	2		2
Balances at Dec. 31, 2016	10,685	$ 33	2,562	11,454	(66)	(3,298)
Balances (in shares) at Dec. 31, 2016		198,495
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,448			2,448
Other comprehensive loss	85				85
Common stock repurchases	(3,365)		(200)			(3,165)
Dividends and dividend equivalents	(232)			(232)
Stock-based compensation	157		157
Restricted stock unit vesting	0		(138)			138
Stock option exercises	$ 64		64
Stock option exercises (in shares)	492	77
Balances at Dec. 31, 2017	$ 9,842	$ 33	$ 2,445	$ 13,670	$ 19	$ (6,325)
Balances (in shares) at Dec. 31, 2017		198,572