Stockholders' Equity - Common Stock Repurchased (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended
	Mar. 10, 2020	Jan. 23, 2019	Mar. 31, 2020	Mar. 31, 2019
Equity [Abstract]
Common stock repurchased under repurchase program (in shares)	44,900,000	3,000,000	47,736,847	5,435,476
Average purchase price per share (in usd per share)			$ 9.66	$ 11.04
Shares repurchased related to employee stock-based compensation plans (in shares)			1,105,119	1,289,391
Average purchase price per share (in usd per share)			$ 10.98	$ 10.95
Common shares issued (in shares)			2,837,562	3,470,664
Remaining authority under the share repurchase program			$ 75