Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Deferred tax assets:
U.S. Federal net operating loss carryforwards	$ 1,395	$ 1,477
State net operating loss carryforwards	326	341
Foreign net operating loss carryforwards	107	106
Deferred revenues	323	335
Difference between book and tax basis of property	101	322
Federal tax credit carryforwards	288	269
Deferred compensation, accrued vacation and other reserves	170	174
Interest disallowance carryforward per §163(j) of the Tax Act	26	77
Pension and other postretirement benefits	33	46
Allowance for credit losses	34	37
Equity compensation	44	30
Federal benefit on state uncertain tax positions	13	13
Inventory obsolescence	9	13
U.S. capital loss	1	1
Other	45	46
Total deferred tax assets	2,915	3,287
Deferred tax liabilities:
Intangibles amortization (excluding goodwill)	338	486
Derivatives	85	193
Capitalized contract costs	345	249
Equity method investments	84	88
Goodwill	71	56
Emissions allowances	14	16
Total deferred tax liabilities	937	1,088
Total deferred tax assets less deferred tax liabilities	1,978	2,199
Valuation allowance	(150)	(144)
Net deferred tax asset	1,828	2,055
NRG's net deferred tax position
Deferred tax asset	1,843	2,067
Deferred tax liability	(15)	(12)
Net deferred tax asset	$ 1,828	$ 2,055