Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities
Net income (loss)	$ 598	$ (264)
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	1,024	2,104
Asset impairments	0	1
Gain on sales of assets and businesses	(10)	(71)
Deferred income taxes and amortization of investment tax credits	110	(142)
Net fair value changes related to derivatives	(59)	(178)
Net realized and unrealized (gains) losses on NDT funds	205	(118)
Net unrealized (gains) losses on equity investments	16	23
Other non-cash operating activities	232	(170)
Changes in assets and liabilities:
Accounts receivable	(711)	(372)
Inventories	125	77
Accounts payable and accrued expenses	291	(176)
Option premiums (paid) received, net	(39)	16
Collateral received (posted), net	1,142	273
Income taxes	77	113
Pension and non-pension postretirement benefit contributions	(574)	(537)
Other assets and liabilities	(645)	(1,840)
Net Cash Provided by (Used in) Operating Activities, Total	1,782	(1,261)
Cash flows from investing activities
Capital expenditures	(1,922)	(2,140)
Proceeds from NDT fund sales	488	2,908
Investment in NDT funds	(516)	(2,939)
Collection of deferred purchase price	169	1,574
Proceeds from Sale of Property Held-for-sale	16	680
Other investing activities	(54)	12
Net Cash Provided by (Used in) Investing Activities, Total	(1,819)	95
Cash flows from financing activities
Changes in short-term borrowings	(700)	597
Proceeds from short-term borrowings with maturities greater than 90 days	1,150	500
Repayments on short-term borrowings with maturities greater than 90 days	(350)	0
Issuance of long-term debt	4,301	1,705
Retirement of long-term debt	(6)	(79)
Dividends paid on common stock	(332)	(374)
Proceeds from employee stock plans	9	31
Transfer of cash, restricted cash, and cash equivalents to Constellation	(2,594)	0
Other financing activities	(62)	(46)
Net cash flows provided by financing activities	1,416	2,334
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	1,379	1,168
Cash, restricted cash, and cash equivalents at beginning of period	1,619	1,166
Cash, restricted cash, and cash equivalents at end of period	2,998	2,334
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(322)	(324)
Increase in deferred purchase price	348	1,339
Increase in PPE related to ARO update	(335)	2
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	207	1,346
Gain on sales of assets and businesses	9	(71)
Deferred income taxes and amortization of investment tax credits	(143)	(234)
Net fair value changes related to derivatives	(59)	(178)
Net realized and unrealized (gains) losses on NDT funds	205	(118)
Net unrealized (gains) losses on equity investments	16	23
Other non-cash operating activities	(36)	332
Cash flows from investing activities
Capital expenditures	(227)	(394)
Collection of deferred purchase price	169	1,574
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(128)	(37)
Increase in deferred purchase price	348	1,339
Increase in PPE related to ARO update	335	0
Commonwealth Edison Co [Member]
Cash flows from operating activities
Net income (loss)	188	197
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	321	292
Deferred income taxes and amortization of investment tax credits	54	63
Other non-cash operating activities	(9)	(9)
Changes in assets and liabilities:
Accounts receivable	(45)	23
Change in receivables from payables to affiliates, net	(42)	(15)
Inventories	3	(1)
Accounts payable and accrued expenses	(154)	(176)
Collateral received (posted), net	43	5
Income taxes	(2)	(23)
Pension and non-pension postretirement benefit contributions	(176)	(171)
Other assets and liabilities	(37)	(159)
Net Cash Provided by (Used in) Operating Activities, Total	144	26
Cash flows from investing activities
Capital expenditures	(617)	(613)
Other investing activities	7	7
Net Cash Provided by (Used in) Investing Activities, Total	(610)	(606)
Cash flows from financing activities
Changes in short-term borrowings	0	(188)
Issuance of long-term debt	750	700
Dividends paid on common stock	(144)	(127)
Contributions from parent	167	198
Other financing activities	(10)	(9)
Net cash flows provided by financing activities	763	574
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	297	(6)
Cash, restricted cash, and cash equivalents at beginning of period	384	405
Cash, restricted cash, and cash equivalents at end of period	681	399
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(50)	(107)
PECO Energy Co [Member]
Cash flows from operating activities
Net income (loss)	206	167
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	92	86
Deferred income taxes and amortization of investment tax credits	14	6
Other non-cash operating activities	15	12
Changes in assets and liabilities:
Accounts receivable	(40)	(5)
Change in receivables from payables to affiliates, net	(31)	(2)
Inventories	27	13
Accounts payable and accrued expenses	(24)	(36)
Income taxes	0	3
Pension and non-pension postretirement benefit contributions	(12)	(16)
Other assets and liabilities	(106)	(103)
Net Cash Provided by (Used in) Operating Activities, Total	141	125
Cash flows from investing activities
Capital expenditures	(344)	(295)
Changes in Exelon/PHI intercompany money pool	0	(48)
Other investing activities	2	1
Net Cash Provided by (Used in) Investing Activities, Total	(342)	(342)
Cash flows from financing activities
Issuance of long-term debt	0	375
Increase (Decrease) in Due to Affiliates, Current	65	(40)
Dividends paid on common stock	(100)	(85)
Contributions from parent	227	0
Other financing activities	(1)	(4)
Net cash flows provided by financing activities	191	246
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	(10)	29
Cash, restricted cash, and cash equivalents at beginning of period	44	26
Cash, restricted cash, and cash equivalents at end of period	34	55
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(41)	(44)
Baltimore Gas and Electric Company [Member]
Cash flows from operating activities
Net income (loss)	198	209
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	171	152
Deferred income taxes and amortization of investment tax credits	5	(4)
Other non-cash operating activities	44	2
Changes in assets and liabilities:
Accounts receivable	(80)	12
Change in receivables from payables to affiliates, net	(2)	(15)
Inventories	32	9
Accounts payable and accrued expenses	(30)	(59)
Income taxes	4	(9)
Pension and non-pension postretirement benefit contributions	(56)	(65)
Other assets and liabilities	(9)	(103)
Net Cash Provided by (Used in) Operating Activities, Total	277	129
Cash flows from investing activities
Capital expenditures	(303)	(336)
Other investing activities	3	2
Net Cash Provided by (Used in) Investing Activities, Total	(300)	(334)
Cash flows from financing activities
Changes in short-term borrowings	120	156
Dividends paid on common stock	(76)	(74)
Other financing activities	(1)	0
Net cash flows provided by financing activities	43	82
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	20	(123)
Cash, restricted cash, and cash equivalents at beginning of period	55	145
Cash, restricted cash, and cash equivalents at end of period	75	22
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(32)	(80)
Pepco Holdings LLC [Member]
Cash flows from operating activities
Net income (loss)	130	128
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	218	210
Deferred income taxes and amortization of investment tax credits	2	4
Other non-cash operating activities	35	(25)
Changes in assets and liabilities:
Accounts receivable	(21)	56
Change in receivables from payables to affiliates, net	(51)	(18)
Inventories	7	5
Accounts payable and accrued expenses	(23)	(24)
Income taxes	5	3
Pension and non-pension postretirement benefit contributions	(67)	(36)
Other assets and liabilities	(3)	(94)
Net Cash Provided by (Used in) Operating Activities, Total	232	209
Cash flows from investing activities
Capital expenditures	(409)	(456)
Other investing activities	2	1
Net Cash Provided by (Used in) Investing Activities, Total	(407)	(455)
Cash flows from financing activities
Changes in short-term borrowings	(468)	(368)
Issuance of long-term debt	700	625
Retirement of long-term debt	0	(44)
Increase (Decrease) in Due to Affiliates, Current	39	3
Payments of Distributions to Affiliates	(102)	(81)
Proceeds from Contributions from Affiliates	704	560
Other financing activities	(9)	(5)
Net cash flows provided by financing activities	864	690
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	689	444
Cash, restricted cash, and cash equivalents at beginning of period	213	160
Cash, restricted cash, and cash equivalents at end of period	902	604
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(55)	(33)
Potomac Electric Power Company [Member]
Cash flows from operating activities
Net income (loss)	46	59
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	102
Deferred income taxes and amortization of investment tax credits	(2)	4
Other non-cash operating activities	12	(25)
Changes in assets and liabilities:
Accounts receivable	(2)	26
Change in receivables from payables to affiliates, net	(25)	(9)
Inventories	0	1
Accounts payable and accrued expenses	5	0
Income taxes	1	2
Pension and non-pension postretirement benefit contributions	(5)	(5)
Other assets and liabilities	(18)	(58)
Net Cash Provided by (Used in) Operating Activities, Total	120	97
Cash flows from investing activities
Capital expenditures	(218)	(220)
Other investing activities	1	1
Net Cash Provided by (Used in) Investing Activities, Total	(217)	(219)
Cash flows from financing activities
Changes in short-term borrowings	(175)	(35)
Issuance of long-term debt	400	150
Dividends paid on common stock	(42)	(28)
Contributions from parent	387	138
Other financing activities	(5)	(1)
Net cash flows provided by financing activities	565	224
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	468	102
Cash, restricted cash, and cash equivalents at beginning of period	68	65
Cash, restricted cash, and cash equivalents at end of period	536	167
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(36)	(16)
Delmarva Power and Light Company [Member]
Cash flows from operating activities
Net income (loss)	56	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	57	53
Deferred income taxes and amortization of investment tax credits	5	2
Other non-cash operating activities	9	(1)
Changes in assets and liabilities:
Accounts receivable	(17)	15
Change in receivables from payables to affiliates, net	(17)	(11)
Inventories	8	2
Accounts payable and accrued expenses	15	11
Income taxes	(1)	3
Pension and non-pension postretirement benefit contributions	(1)	0
Other assets and liabilities	33	(26)
Net Cash Provided by (Used in) Operating Activities, Total	147	104
Cash flows from investing activities
Capital expenditures	(103)	(112)
Other investing activities	1	0
Net Cash Provided by (Used in) Investing Activities, Total	(102)	(112)
Cash flows from financing activities
Changes in short-term borrowings	(149)	(146)
Issuance of long-term debt	125	125
Dividends paid on common stock	(41)	(40)
Contributions from parent	144	120
Other financing activities	(2)	(2)
Net cash flows provided by financing activities	77	57
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	122	49
Cash, restricted cash, and cash equivalents at beginning of period	71	15
Cash, restricted cash, and cash equivalents at end of period	193	64
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(8)	(15)
Atlantic City Electric Company [Member]
Cash flows from operating activities
Net income (loss)	26	14
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	47	47
Deferred income taxes and amortization of investment tax credits	1	(1)
Other non-cash operating activities	2	(7)
Changes in assets and liabilities:
Accounts receivable	(1)	13
Change in receivables from payables to affiliates, net	(6)	1
Inventories	(1)	3
Accounts payable and accrued expenses	(17)	(11)
Income taxes	0	1
Pension and non-pension postretirement benefit contributions	(7)	(3)
Other assets and liabilities	0	(3)
Net Cash Provided by (Used in) Operating Activities, Total	44	54
Cash flows from investing activities
Capital expenditures	(87)	(123)
Net Cash Provided by (Used in) Investing Activities, Total	(87)	(123)
Cash flows from financing activities
Changes in short-term borrowings	(144)	(187)
Issuance of long-term debt	175	350
Retirement of long-term debt	0	(44)
Dividends paid on common stock	(19)	(14)
Contributions from parent	173	303
Other financing activities	(3)	(3)
Net cash flows provided by financing activities	182	405
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	139	336
Cash, restricted cash, and cash equivalents at beginning of period	29	30
Cash, restricted cash, and cash equivalents at end of period	168	366
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	$ (10)	$ (2)