Consolidated Statements of Changes in Equity - NPC - USD ($) $ in Millions	Total	Additional Paid-in Capital	Retained Earnings	NPC	NPC Common Stock	NPC Additional Paid-in Capital	NPC Retained Earnings	NPC Accumulated Other Comprehensive Income (Loss)
Balance (shares) at Dec. 31, 2019					1,000
Balance at Dec. 31, 2019				$ 2,797	$ 0	$ 2,308	$ 493	$ (4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to parent	$ 6,943			295			295
Dividends declared				(155)			(155)
Other equity transactions	0	$ (1)		2			1	1
Balance (shares) at Dec. 31, 2020					1,000
Balance at Dec. 31, 2020				2,939	$ 0	2,308	634	(3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to parent	5,790			303			303
Dividends declared				(213)			(213)
Other equity transactions	$ (1)			$ 1				1
Balance (shares) at Dec. 31, 2021	76,000,000			1,000	1,000
Balance at Dec. 31, 2021	$ 46,694			$ 3,030	$ 0	2,308	724	(2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to parent	2,721			298			298
Contributions				25		25
Other equity transactions	$ (12)	$ 1	$ (12)	$ 1				1
Balance (shares) at Dec. 31, 2022	76,000,000			1,000	1,000
Balance at Dec. 31, 2022	$ 46,832			$ 3,354	$ 0	$ 2,333	$ 1,022	$ (1)