Consolidated Statements Of Shareholders' Equity (Parenthetical) - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Stockholders' Equity [Abstract]
Issuance of common stock under stock option and benefit plans, shares	1,700	1,800	2,200
Issuance of common stock under stock option and benefit plans, excess income tax benefit	$ 36	$ 26	$ 21
Repurchase and retirement of common stock, shares	135	7,400	1,300
Cash dividends declared, per share of common stock	$ 1.565	$ 1.415	$ 1.26