Equity - Share Repurchase Program and Share Repurchase Activity (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 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	$ 900,000,000		$ 900,000,000
Number of shares repurchased (in shares)	11,087	524,435	223,511	763,703
Cash paid for repurchased shares (in thousands)	$ 1,719,000	$ 67,877,000	$ 46,558,000	$ 96,271,000
Treasury stock, average price paid per share (in dollars per share)	$ 155.37	$ 131.23	$ 141.20	$ 127.29