Consolidated Statements of Changes in Equity (Unaudited) - NPC - USD ($) $ in Millions	Total	NPC	NPC Common Stock	NPC Additional Paid-in Capital	NPC Retained Earnings	NPC Accumulated Other Comprehensive (Loss) Income, Net
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 (loss)	$ 4,207	301			301
Dividends declared		(13)			(13)
Balance (shares) at Sep. 30, 2021			1,000
Balance at Sep. 30, 2021		3,227	$ 0	2,308	922	(3)
Balance (shares) at Jun. 30, 2021			1,000
Balance at Jun. 30, 2021		3,010	$ 0	2,308	705	(3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 1,922	217			217
Balance (shares) at Sep. 30, 2021			1,000
Balance at Sep. 30, 2021		$ 3,227	$ 0	2,308	922	(3)
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 (loss)	$ 1,926	283			283
Contributions		$ 25		25
Balance (shares) at Sep. 30, 2022	76,000,000	1,000	1,000
Balance at Sep. 30, 2022	$ 45,858	$ 3,338	$ 0	2,333	1,007	(2)
Balance (shares) at Jun. 30, 2022			1,000
Balance at Jun. 30, 2022		3,129	$ 0	2,333	798	(2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ (842)	$ 209			209
Balance (shares) at Sep. 30, 2022	76,000,000	1,000	1,000
Balance at Sep. 30, 2022	$ 45,858	$ 3,338	$ 0	$ 2,333	$ 1,007	$ (2)