Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities
Net income (loss)	$ 669	$ 598
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	860	1,024
Gain on sales of assets and businesses	0	(10)
Deferred income taxes and amortization of investment tax credits	113	110
Net fair value changes related to derivatives	0	(59)
Net realized and unrealized (gains) losses on NDT funds	0	205
Net unrealized (gains) losses on equity investments	0	16
Other non-cash operating activities	(138)	232
Changes in assets and liabilities:
Accounts receivable	106	(711)
Inventories	102	125
Accounts payable and accrued expenses	(482)	291
Option premiums paid, net	0	(39)
Collateral received (posted), net	(214)	1,142
Income taxes	23	77
Regulatory assets and liabilities, net	(324)	(31)
Pension and non-pension postretirement benefit contributions	(44)	(574)
Other assets and liabilities	(187)	(614)
Net Cash Provided by (Used in) Operating Activities, Total	484	1,782
Cash flows from investing activities
Capital expenditures	(1,881)	(1,922)
Proceeds from NDT fund sales	0	488
Investment in NDT funds	0	(516)
Collection of deferred purchase price	0	169
Proceeds from Sale of Property Held-for-sale	0	16
Other investing activities	10	(54)
Net Cash Provided by (Used in) Investing Activities, Total	(1,871)	(1,819)
Cash flows from financing activities
Changes in short-term borrowings	(1,130)	(700)
Proceeds from short-term borrowings with maturities greater than 90 days	0	1,150
Repayments on short-term borrowings with maturities greater than 90 days	(150)	(350)
Issuance of long-term debt	3,925	4,301
Retirement of long-term debt	(857)	(6)
Dividends paid on common stock	(358)	(332)
Proceeds from employee stock plans	10	9
Transfer of cash, restricted cash, and cash equivalents to Constellation	0	(2,594)
Other financing activities	(60)	(62)
Net cash flows provided by financing activities	1,380	1,416
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	(7)	1,379
Cash, restricted cash, and cash equivalents at beginning of period	1,090	1,619
Cash, restricted cash, and cash equivalents at end of period	1,083	2,998
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(201)	(322)
Increase in deferred purchase price	0	348
Increase in PPE related to ARO update	0	(335)
Exelon Generation Co L L C [Member]
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	0	207
Gain on sales of assets and businesses	0	9
Deferred income taxes and amortization of investment tax credits	0	(143)
Net fair value changes related to derivatives	0	(59)
Net realized and unrealized (gains) losses on NDT funds	0	205
Net unrealized (gains) losses on equity investments	0	16
Other non-cash operating activities	0	(36)
Cash flows from investing activities
Capital expenditures	0	(227)
Collection of deferred purchase price	0	169
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	0	(128)
Increase in deferred purchase price	0	348
Increase in PPE related to ARO update	0	335
Commonwealth Edison Co [Member]
Cash flows from operating activities
Net income (loss)	241	188
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	338	321
Deferred income taxes and amortization of investment tax credits	55	54
Other non-cash operating activities	(153)	(9)
Changes in assets and liabilities:
Accounts receivable	96	(45)
Receivables from payables to affiliates, net	10	(42)
Inventories	(21)	3
Accounts payable and accrued expenses	(306)	(154)
Collateral received (posted), net	(4)	43
Income taxes	15	(2)
Regulatory assets and liabilities, net	(338)	(8)
Pension and non-pension postretirement benefit contributions	(23)	(176)
Other assets and liabilities	(22)	(29)
Net Cash Provided by (Used in) Operating Activities, Total	(112)	144
Cash flows from investing activities
Capital expenditures	(617)	(617)
Other investing activities	1	7
Net Cash Provided by (Used in) Investing Activities, Total	(616)	(610)
Cash flows from financing activities
Changes in short-term borrowings	(18)	0
Repayments on short-term borrowings with maturities greater than 90 days	(150)	0
Issuance of long-term debt	975	750
Dividends paid on common stock	(187)	(144)
Contributions from parent	186	167
Other financing activities	(11)	(10)
Net cash flows provided by financing activities	795	763
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	67	297
Cash, restricted cash, and cash equivalents at beginning of period	511	384
Cash, restricted cash, and cash equivalents at end of period	578	681
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(35)	(50)
PECO Energy Co [Member]
Cash flows from operating activities
Net income (loss)	166	206
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	98	92
Deferred income taxes and amortization of investment tax credits	(16)	14
Other non-cash operating activities	32	15
Changes in assets and liabilities:
Accounts receivable	36	(40)
Receivables from payables to affiliates, net	8	(31)
Inventories	60	27
Accounts payable and accrued expenses	(176)	(24)
Income taxes	20	0
Regulatory assets and liabilities, net	15	(4)
Pension and non-pension postretirement benefit contributions	0	(12)
Other assets and liabilities	(75)	(102)
Net Cash Provided by (Used in) Operating Activities, Total	168	141
Cash flows from investing activities
Capital expenditures	(335)	(344)
Other investing activities	0	2
Net Cash Provided by (Used in) Investing Activities, Total	(335)	(342)
Cash flows from financing activities
Changes in short-term borrowings	(94)	0
Increase (Decrease) in Due to Affiliates, Current	0	65
Dividends paid on common stock	(101)	(100)
Contributions from parent	330	227
Other financing activities	0	(1)
Net cash flows provided by financing activities	135	191
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	(32)	(10)
Cash, restricted cash, and cash equivalents at beginning of period	68	44
Cash, restricted cash, and cash equivalents at end of period	36	34
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(9)	(41)
Baltimore Gas and Electric Company [Member]
Cash flows from operating activities
Net income (loss)	200	198
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	167	171
Deferred income taxes and amortization of investment tax credits	24	5
Other non-cash operating activities	(32)	44
Changes in assets and liabilities:
Accounts receivable	43	(80)
Receivables from payables to affiliates, net	(3)	(2)
Inventories	62	32
Accounts payable and accrued expenses	(96)	(30)
Collateral received (posted), net	(22)	30
Income taxes	29	4
Regulatory assets and liabilities, net	(31)	(8)
Pension and non-pension postretirement benefit contributions	(8)	(56)
Other assets and liabilities	(24)	(31)
Net Cash Provided by (Used in) Operating Activities, Total	309	277
Cash flows from investing activities
Capital expenditures	(350)	(303)
Other investing activities	3	3
Net Cash Provided by (Used in) Investing Activities, Total	(347)	(300)
Cash flows from financing activities
Changes in short-term borrowings	(165)	120
Dividends paid on common stock	(80)	(76)
Contributions from parent	237	0
Other financing activities	0	(1)
Net cash flows provided by financing activities	(8)	43
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	(46)	20
Cash, restricted cash, and cash equivalents at beginning of period	67	55
Cash, restricted cash, and cash equivalents at end of period	21	75
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(70)	(32)
Pepco Holdings LLC [Member]
Cash flows from operating activities
Net income (loss)	155	130
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	241	218
Deferred income taxes and amortization of investment tax credits	13	2
Other non-cash operating activities	(7)	35
Changes in assets and liabilities:
Accounts receivable	98	(21)
Receivables from payables to affiliates, net	0	(51)
Inventories	4	7
Accounts payable and accrued expenses	(88)	(23)
Collateral received (posted), net	(189)	37
Income taxes	20	5
Regulatory assets and liabilities, net	27	(18)
Pension and non-pension postretirement benefit contributions	(7)	(67)
Other assets and liabilities	(11)	(22)
Net Cash Provided by (Used in) Operating Activities, Total	256	232
Cash flows from investing activities
Capital expenditures	(561)	(409)
Other investing activities	8	2
Net Cash Provided by (Used in) Investing Activities, Total	(553)	(407)
Cash flows from financing activities
Changes in short-term borrowings	(414)	(468)
Issuance of long-term debt	450	700
Increase (Decrease) in Due to Affiliates, Current	8	39
Payments of Distributions to Affiliates	(112)	(102)
Proceeds from Contributions from Affiliates	405	704
Other financing activities	(17)	(9)
Net cash flows provided by financing activities	320	864
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	23	689
Cash, restricted cash, and cash equivalents at beginning of period	373	213
Cash, restricted cash, and cash equivalents at end of period	396	902
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(76)	(55)
Potomac Electric Power Company [Member]
Cash flows from operating activities
Net income (loss)	65	46
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	108	108
Deferred income taxes and amortization of investment tax credits	3	(2)
Other non-cash operating activities	(10)	12
Changes in assets and liabilities:
Accounts receivable	52	(2)
Receivables from payables to affiliates, net	3	(25)
Inventories	(3)	0
Accounts payable and accrued expenses	(27)	5
Collateral received (posted), net	(25)	1
Income taxes	8	1
Regulatory assets and liabilities, net	(3)	(7)
Pension and non-pension postretirement benefit contributions	(4)	(5)
Other assets and liabilities	11	(12)
Net Cash Provided by (Used in) Operating Activities, Total	178	120
Cash flows from investing activities
Capital expenditures	(264)	(218)
Other investing activities	8	1
Net Cash Provided by (Used in) Investing Activities, Total	(256)	(217)
Cash flows from financing activities
Changes in short-term borrowings	(299)	(175)
Issuance of long-term debt	250	400
Dividends paid on common stock	(48)	(42)
Contributions from parent	243	387
Other financing activities	(14)	(5)
Net cash flows provided by financing activities	132	565
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	54	468
Cash, restricted cash, and cash equivalents at beginning of period	99	68
Cash, restricted cash, and cash equivalents at end of period	153	536
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(43)	(36)
Delmarva Power and Light Company [Member]
Cash flows from operating activities
Net income (loss)	60	56
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	60	57
Deferred income taxes and amortization of investment tax credits	3	5
Other non-cash operating activities	(1)	9
Changes in assets and liabilities:
Accounts receivable	23	(17)
Receivables from payables to affiliates, net	4	(17)
Inventories	10	8
Accounts payable and accrued expenses	(16)	15
Collateral received (posted), net	(120)	30
Income taxes	9	(1)
Regulatory assets and liabilities, net	27	0
Pension and non-pension postretirement benefit contributions	0	(1)
Other assets and liabilities	1	3
Net Cash Provided by (Used in) Operating Activities, Total	60	147
Cash flows from investing activities
Capital expenditures	(134)	(103)
Other investing activities	0	1
Net Cash Provided by (Used in) Investing Activities, Total	(134)	(102)
Cash flows from financing activities
Changes in short-term borrowings	(115)	(149)
Issuance of long-term debt	125	125
Dividends paid on common stock	(42)	(41)
Contributions from parent	99	144
Other financing activities	(2)	(2)
Net cash flows provided by financing activities	65	77
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	(9)	122
Cash, restricted cash, and cash equivalents at beginning of period	152	71
Cash, restricted cash, and cash equivalents at end of period	143	193
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(3)	(8)
Atlantic City Electric Company [Member]
Cash flows from operating activities
Net income (loss)	33	26
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	67	47
Deferred income taxes and amortization of investment tax credits	6	1
Other non-cash operating activities	(9)	2
Changes in assets and liabilities:
Accounts receivable	24	(1)
Receivables from payables to affiliates, net	(1)	(6)
Inventories	(3)	(1)
Accounts payable and accrued expenses	(15)	(17)
Collateral received (posted), net	(44)	(3)
Income taxes	5	0
Regulatory assets and liabilities, net	3	(3)
Pension and non-pension postretirement benefit contributions	(1)	(7)
Other assets and liabilities	(21)	6
Net Cash Provided by (Used in) Operating Activities, Total	44	44
Cash flows from investing activities
Capital expenditures	(161)	(87)
Net Cash Provided by (Used in) Investing Activities, Total	(161)	(87)
Cash flows from financing activities
Changes in short-term borrowings	0	(144)
Issuance of long-term debt	75	175
Dividends paid on common stock	(21)	(19)
Contributions from parent	63	173
Other financing activities	(1)	(3)
Net cash flows provided by financing activities	116	182
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	(1)	139
Cash, restricted cash, and cash equivalents at beginning of period	72	29
Cash, restricted cash, and cash equivalents at end of period	71	168
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	$ (30)	$ (10)