Consolidated Statements of Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Stockholders' Equity [Abstract]
Net issuances of shares held in treasury in settlement of stock-based compensation (in shares)	374,267	456,252	783,793
Number of Shares	4,308,418	3,014,131	5,816,363
Repurchases of shares of common stock, average price (in dollars per share)	$ 163.69	$ 150.77	$ 113.26
Retirement of shares held in treasury (in shares)	8,000,000	8,000,000
Retirement of shares held in treasury, average price (in dollars per share)	$ 146.27	$ 111.43