Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock	Preferred Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Balance at beginning of period at Dec. 31, 2021	$ 13,794	$ 0	$ 0	$ 8,692	$ (1,273)	$ 6,375
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	962					962
Other comprehensive income (loss)	238				238
Stock-based compensation	10			10
Balance at end of period at Mar. 31, 2022	15,004	0	0	8,701	(1,034)	7,337
Balance at beginning of period at Dec. 31, 2022	15,010	0	0	8,742	(1,373)	7,641
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	584					584
Other comprehensive income (loss)	49				49
Stock-based compensation	7			7
Dividends paid (Note 10)	(450)					(450)
Balance at end of period at Mar. 31, 2023	$ 15,201	$ 0	$ 0	$ 8,749	$ (1,323)	$ 7,775