Equity - Share Repurchase Program and Share Repurchase Activity (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	May 31, 2015
Stockholders' Equity Note [Abstract]
Stock repurchase program, authorized amount					$ 1,200,000,000
Stock repurchase program, remaining authorized repurchase amount	$ 800,000,000		$ 800,000,000
Number of shares repurchased (in shares)	705,800	51,298	929,311	815,001
Cash paid for repurchased shares	$ 94,878,000	$ 8,129,000	$ 141,436,000	$ 104,400,000
Treasury stock, average price paid per share (in dollars per share)	$ 134.42	$ 140.09	$ 136.05	$ 128.10