SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF PARENT - STATEMENT OF OPERATIONS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Condensed Income Statements, Captions [Line Items]
Interest income	$ 69	$ 96	$ 87
Interest expense	(1,198)	(1,081)	(1,077)
Other income (expense), net	58	(48)	77
Income tax benefit (expense)	(99)	(249)	(315)
Income from continuing operations, net of tax	1,463	2,255	1,999
Net income	$ 1,463	$ 4,105	$ 2,362
Basic earnings per common share (in shares)	$ 4.03	$ 12.93	$ 7.40
Weighted-average number of shares outstanding, basic (in shares)	311,755	291,077	277,904
Diluted earnings per common share (in dollars per share)	$ 4.01	$ 12.88	$ 7.29
Weighted-average number of shares outstanding, diluted (in shares)	313,036	292,252	282,033
Parent Company
Condensed Income Statements, Captions [Line Items]
Interest income	$ 11	$ 4	$ 3
Interest expense	(576)	(495)	(521)
Operating expenses	(92)	(86)	(124)
Other income (expense), net	20	(38)	59
Income tax benefit (expense)	190	176	163
Income from continuing operations, net of tax	(447)	(439)	(420)
Equity in earnings of subsidiaries, net of income taxes	1,764	4,371	2,617
Net income	1,317	3,932	2,197
Preferred dividends	(63)	(168)	(142)
Earnings attributable to common shares	$ 1,254	$ 3,764	$ 2,055
Basic earnings per common share (in shares)	$ 4.03	$ 12.93	$ 7.40
Weighted-average number of shares outstanding, basic (in shares)	311,755	291,077	277,904
Diluted earnings per common share (in dollars per share)	$ 4.01	$ 12.88	$ 7.29
Weighted-average number of shares outstanding, diluted (in shares)	313,036	292,252	282,033