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Fair Value of Financial Assets and Liabilities - Fair Value Measurement of Assets and Liabilities, Recurring (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]
Derivative asset notational amounts	$ 1,254	$ 1,119
Cash and Cash Equivalents | Constellation Energy Generation, LLC
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	1,817	2,924
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	1,817	2,924
Cash and Cash Equivalents | CEG Parent
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	38	130
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	38	130
Restricted cash | Constellation Energy Generation, LLC
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	77	71
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	77	71
Cash | CEG Parent
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	10	4
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	10	4
NDT fund investments subtotal
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]
Net liabilities	162	148
Fair Value, Recurring
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	28	120
Deferred compensation obligation	(89)	(93)
Total liabilities measured at fair value	(997)	(959)
Total net assets	18,083	18,186
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	28	120
Fair Value, Recurring | Mark-to-market derivative liabilities subtotal
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative liabilities	(908)	(866)
Fair Value, Recurring | Economic hedges
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative liabilities	(13,366)	(9,462)
Fair Value, Recurring | Effect of netting and allocation of collateral
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative liabilities	12,458	8,596
Fair Value, Recurring | NDT fund investments subtotal
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	17,512	17,321
Fair Value, Recurring | Cash equivalents
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	395	350
Fair Value, Recurring | Equities NDT
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	7,004	7,127
Fair Value, Recurring | Fixed income
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	3,998	3,919
Fair Value, Recurring | Private credit
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	128	134
Fair Value, Recurring | Rabbi trust investments
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	99	100
Fair Value, Recurring | Investments in equities
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	98	389
Fair Value, Recurring | Mark-to-market derivative assets subtotal
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative assets	1,343	1,215
Fair Value, Recurring | Economic hedges
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative assets	12,738	9,225
Fair Value, Recurring | Effect of netting and allocation of collateral
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative assets	(11,395)	(8,010)
Total assets measured at fair value | Fair Value, Recurring
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Total assets	19,080	19,145
Level 1 | Fair Value, Recurring
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	28	120
Total assets	8,225	8,254
Deferred compensation obligation	0	0
Total liabilities measured at fair value	(72)	(42)
Total net assets	8,153	8,212
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	28	120
Level 1 | Fair Value, Recurring | Mark-to-market derivative liabilities subtotal
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative liabilities	(72)	(42)
Level 1 | Fair Value, Recurring | Economic hedges
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative liabilities	(1,947)	(1,222)
Level 1 | Fair Value, Recurring | Effect of netting and allocation of collateral
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative liabilities	1,875	1,180
Level 1 | Fair Value, Recurring | NDT fund investments subtotal
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	7,689	7,506
Level 1 | Fair Value, Recurring | Cash equivalents
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	227	187
Level 1 | Fair Value, Recurring | Equities NDT
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	5,351	5,230
Level 1 | Fair Value, Recurring | Fixed income
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	2,111	2,089
Level 1 | Fair Value, Recurring | Private credit
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	0	0
Level 1 | Fair Value, Recurring | Rabbi trust investments
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	58	58
Level 1 | Fair Value, Recurring | Investments in equities
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	98	389
Level 1 | Fair Value, Recurring | Mark-to-market derivative assets subtotal
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative assets	352	181
Level 1 | Fair Value, Recurring | Economic hedges
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative assets	1,986	1,278
Level 1 | Fair Value, Recurring | Effect of netting and allocation of collateral
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative assets	(1,634)	(1,097)
Level 2 | Fair Value, Recurring
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	0	0
Total assets	3,856	4,079
Deferred compensation obligation	(89)	(93)
Total liabilities measured at fair value	(398)	(398)
Total net assets	3,458	3,681
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	0	0
Level 2 | Fair Value, Recurring | Mark-to-market derivative liabilities subtotal
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative liabilities	(309)	(305)
Level 2 | Fair Value, Recurring | Economic hedges
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative liabilities	(7,939)	(5,462)
Level 2 | Fair Value, Recurring | Effect of netting and allocation of collateral
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative liabilities	7,630	5,157
Level 2 | Fair Value, Recurring | NDT fund investments subtotal
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	3,334	3,522
Level 2 | Fair Value, Recurring | Cash equivalents
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	168	163
Level 2 | Fair Value, Recurring | Equities NDT
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	1,652	1,897
Level 2 | Fair Value, Recurring | Fixed income
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	1,514	1,462
Level 2 | Fair Value, Recurring | Private credit
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	0	0
Level 2 | Fair Value, Recurring | Rabbi trust investments
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	40	41
Level 2 | Fair Value, Recurring | Investments in equities
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	0	0
Level 2 | Fair Value, Recurring | Mark-to-market derivative assets subtotal
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative assets	482	516
Level 2 | Fair Value, Recurring | Economic hedges
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative assets	7,493	5,306
Level 2 | Fair Value, Recurring | Effect of netting and allocation of collateral
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative assets	(7,011)	(4,790)
Level 3 | Fair Value, Recurring
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	0	0
Total assets	1,012	1,021
Deferred compensation obligation	0	0
Total liabilities measured at fair value	(527)	(519)
Total net assets	485	502
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]
Cash equivalents, fair value disclosure	0	0
Level 3 | Fair Value, Recurring | Mark-to-market derivative liabilities subtotal
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative liabilities	(527)	(519)
Level 3 | Fair Value, Recurring | Economic hedges
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative liabilities	(3,480)	(2,778)
Level 3 | Fair Value, Recurring | Effect of netting and allocation of collateral
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative liabilities	2,953	2,259
Level 3 | Fair Value, Recurring | NDT fund investments subtotal
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	502	502
Level 3 | Fair Value, Recurring | Cash equivalents
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	0	0
Level 3 | Fair Value, Recurring | Equities NDT
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	1	0
Level 3 | Fair Value, Recurring | Fixed income
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	373	368
Level 3 | Fair Value, Recurring | Private credit
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	128	134
Level 3 | Fair Value, Recurring | Rabbi trust investments
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	1	1
Level 3 | Fair Value, Recurring | Investments in equities
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, fair value disclosure	0	0
Level 3 | Fair Value, Recurring | Mark-to-market derivative assets subtotal
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative assets	509	518
Level 3 | Fair Value, Recurring | Economic hedges
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative assets	3,259	2,641
Level 3 | Fair Value, Recurring | Effect of netting and allocation of collateral
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative assets	(2,750)	(2,123)
Assets measured at NAV | Fair Value, Recurring
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Total assets	$ 5,987	$ 5,791

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Fair value portion of asset recognized for present right to economic benefit.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date.

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Nominal or face amount used to calculate payments on the derivative asset.

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