Share Repurchase Programs and Cash Dividends (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended	3 Months Ended					9 Months Ended
	Feb. 19, 2020	Jan. 31, 2020	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Equity [Abstract]
Stock repurchased (in shares)				6,378,025	7,275,610		16,947,393	6,400,000
Aggregate stock repurchase price				$ 145	$ 201		$ 610	$ 145
Average cost per share (in dollars per share)								$ 22.77
Cash dividends declared per common share (in dollars per share)		$ 0.10	$ 0	$ 0.10	$ 0.10	$ 0.10	$ 0.10	$ 0.10	$ 0.30
Payment of dividends	$ 43