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, 2021			1,000
Balance at Dec. 31, 2021		$ 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			1,000
Balance at Sep. 30, 2022		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			1,000
Balance at Sep. 30, 2022		$ 3,338	$ 0	2,333	1,007	(2)
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)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 2,558	281			281
Contributions		$ 400		400
Balance (shares) at Sep. 30, 2023	76,000,000	1,000	1,000
Balance at Sep. 30, 2023	$ 48,643	$ 4,035	$ 0	2,733	1,303	(1)
Balance (shares) at Jun. 30, 2023			1,000
Balance at Jun. 30, 2023		3,824	$ 0	2,733	1,092	(1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 494	$ 211			211
Balance (shares) at Sep. 30, 2023	76,000,000	1,000	1,000
Balance at Sep. 30, 2023	$ 48,643	$ 4,035	$ 0	$ 2,733	$ 1,303	$ (1)