Stockholders' Equity - Common Stock Repurchased (Details) - USD ($) $ / shares in Units, $ in Millions				3 Months Ended
	Jan. 28, 2021	Mar. 11, 2020	Mar. 10, 2020	Mar. 31, 2021	Mar. 31, 2020
Equity [Abstract]
Common stock repurchased under repurchase program (in shares)	13,000,000	45,000,000	45,000,000	48,702,830	47,736,847
Average purchase price per share (in usd per share)				$ 15.75	$ 9.66
Shares repurchased related to employee stock-based compensation plans (in shares)				1,059,980	1,105,119
Average purchase price per share (in usd per share)				$ 13.50	$ 10.98
Common shares issued (in shares)				2,826,387	2,837,562
Remaining authority under the share repurchase program				$ 734
Common stock repurchased and cancelled (in shares)				28,500,000