Stockholders' Equity - Common Stock Repurchased (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Class of Stock [Line Items]
Common stock repurchased under repurchase programs (in shares)	19,997,008	22,806,841	29,530,400	71,509,671
Average purchase price per share (in usd per share)	$ 18.01	$ 19.27	$ 18.15	$ 16.87
Shares repurchased related to employee stock-based compensation plans (in shares)	196,301	192,432	1,130,903	1,252,412
Average purchase price per share (in usd per share)	$ 17.45	$ 18.80	$ 18.36	$ 14.32
Common shares issued (in shares)	493,893	454,920	3,088,710	3,281,307
Remaining authority under the share repurchase program	$ 753		$ 753
Common stock repurchased and cancelled (in shares)				28,500,000
2021 Share Repurchase Program, Accelerated Purchases
Class of Stock [Line Items]
Common stock repurchased under repurchase programs (in shares)				13,000,000