Consolidated Statements of Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Stockholders' Equity [Abstract]
Issuance of shares held in treasury in settlement of stock-based compensation (in shares)	783,793	807,015	868,746
Repurchase of common stock (in shares)	5,816,363	4,366,365	3,805,114
Repurchase of common stock, average price (in dollars per share)	$ 113.26	$ 111.62	$ 93.52
Retirement of shares held in treasury (in shares)			8,000,000
Retirement of shares held in treasury, average price (in dollars per share)			$ 64.98