Condensed Statements of Consolidated Changes in Equity - USD ($) $ in Millions	Total	Series A Preferred Stock	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	AOCI Attributable to Parent
Balance, beginning of period (in shares) at Dec. 31, 2020			3,000,000
Balance, beginning of period at Dec. 31, 2020			$ 2,363	$ 6	$ 6,914	$ (845)	$ (90)
Balance, end of period (in shares) at Mar. 31, 2021			3,000,000
Balance, beginning of period (in shares) at Dec. 31, 2020				551,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances related to benefit and investment plans (in shares)				1,000,000
Issuances related to benefit and investment plans				$ 0	2
Net income	$ 363					363
Other comprehensive income (loss)							3
Balance, end of period (in shares) at Mar. 31, 2021				552,000,000
Balance, end of period at Mar. 31, 2021	$ 8,716		$ 2,363	$ 6	6,916	(482)	(87)
Balance, beginning of period (in shares) at Dec. 31, 2021	800,000	800,000	1,000,000
Balance, beginning of period at Dec. 31, 2021	$ 9,415		$ 790	$ 6	8,529	154	(64)
Balance, end of period (in shares) at Mar. 31, 2022	800,000	800,000	1,000,000
Balance, beginning of period (in shares) at Dec. 31, 2021	628,923,534			629,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances related to benefit and investment plans (in shares)				0
Issuances related to benefit and investment plans				$ 0	3
Net income	$ 531					531
Other comprehensive income (loss)							2
Balance, end of period (in shares) at Mar. 31, 2022	629,432,406			629,000,000
Balance, end of period at Mar. 31, 2022	$ 9,951		$ 790	$ 6	$ 8,532	$ 685	$ (62)