Equity - Narrative (Details) - USD ($) shares in Thousands	3 Months Ended												6 Months Ended			9 Months Ended			12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Payments relating to treasury shares (in shares)																			1,000	1,500	1,500
Stock repurchase program, authorized amount	$ 2,400,000,000					$ 2,000,000,000.0				$ 1,200,000,000							$ 2,000,000,000.0	$ 1,200,000,000	$ 2,400,000,000
Repurchases of common stock (in shares)	3,661	3,730	4,170	5,871	1,863	3,991	6,298	4,105	3,498	3,642	3,916	3,911	10,041	10,403	7,828	13,771	14,394	11,469	17,432	16,257	14,967
Repurchases of common stock	$ 340,000,000	$ 340,000,000	$ 340,000,000	$ 440,000,000	$ 139,000,000	$ 300,000,000	$ 459,000,000	$ 300,000,000	$ 240,000,000	$ 240,000,000	$ 240,000,000	$ 229,000,000							$ 1,460,000,000	$ 1,198,000,000	$ 949,000,000