Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	OPIC	AOCI	Accumulated Deficit
Beginning balance, (in shares) at Dec. 31, 2019		541,000,000
Beginning balance at Dec. 31, 2019	$ 6,975	$ 54	$ 10,868	$ 20	$ (3,967)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	74				74
Other comprehensive loss, net of tax	(18)			(18)
Stock Investment Plan and share-based benefit plans (in shares)		1,000,000
Stock Investment Plan and share-based benefit plans	(6)		(6)
Cash dividends declared on common stock	(211)		(211)
Ending balance (in shares) at Mar. 31, 2020		542,000,000
Ending balance at Mar. 31, 2020	$ 6,814	$ 54	10,651	2	(3,893)
Beginning balance, (in shares) at Dec. 31, 2020	543,117,533	543,000,000
Beginning balance at Dec. 31, 2020	$ 7,237	$ 54	10,076	(5)	(2,888)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	335				335
Other comprehensive loss, net of tax	(2)			(2)
Stock Investment Plan and share-based benefit plans (in shares)		1,000,000
Share-based benefit plans	2		2
Cash dividends declared on common stock	$ (212)		(212)
Ending balance (in shares) at Mar. 31, 2021	543,900,432	544,000,000
Ending balance at Mar. 31, 2021	$ 7,360	$ 54	$ 9,866	$ (7)	$ (2,553)