Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities
Net income (loss)	$ 1,063	$ 211
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	1,854	4,180
Asset impairments	0	500
Gain on sales of assets and businesses	(8)	(83)
Deferred income taxes and amortization of investment tax credits	143	(163)
Net fair value changes related to derivatives	(59)	(490)
Net realized and unrealized (gains) losses on NDT funds	205	(376)
Net unrealized (gains) losses on equity investments	16	(96)
Other non-cash operating activities	276	(331)
Changes in assets and liabilities:
Accounts receivable	(795)	(16)
Inventories	12	1
Accounts payable and accrued expenses	544	(87)
Option premiums (paid) received, net	(39)	2
Collateral received (posted), net	1,689	957
Income taxes	23	190
Regulatory assets and liabilities, net	(376)	(276)
Pension and non-pension postretirement benefit contributions	(585)	(559)
Other assets and liabilities	(723)	(2,426)
Net Cash Provided by (Used in) Operating Activities, Total	3,240	1,138
Cash flows from investing activities
Capital expenditures	(3,507)	(4,040)
Proceeds from NDT fund sales	488	4,438
Investment in NDT funds	(516)	(4,538)
Collection of deferred purchase price	169	2,209
Proceeds from Sale of Property Held-for-sale	16	724
Other investing activities	4	17
Net Cash Provided by (Used in) Investing Activities, Total	(3,346)	(1,190)
Cash flows from financing activities
Changes in short-term borrowings	(597)	(666)
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	5,151	2,455
Retirement of long-term debt	(1,707)	(630)
Dividends paid on common stock	(663)	(747)
Proceeds from employee stock plans	17	47
Transfer of cash, restricted cash, and cash equivalents to Constellation	(2,594)	0
Other financing activities	(84)	(64)
Net cash flows provided by financing activities	323	895
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	217	843
Cash, restricted cash, and cash equivalents at beginning of period	1,619	1,166
Cash, restricted cash, and cash equivalents at end of period	1,836	2,009
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(276)	(313)
Increase in deferred purchase price	348	1,958
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	2,686
Gain on sales of assets and businesses	9	(79)
Deferred income taxes and amortization of investment tax credits	(143)	(268)
Net fair value changes related to derivatives	(59)	(490)
Net realized and unrealized (gains) losses on NDT funds	205	(376)
Net unrealized (gains) losses on equity investments	16	(96)
Other non-cash operating activities	(36)	636
Cash flows from investing activities
Capital expenditures	(227)	(731)
Collection of deferred purchase price	169	2,209
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(128)	(66)
Increase in deferred purchase price	348	1,958
Increase in PPE related to ARO update	335	0
Commonwealth Edison Co [Member]
Cash flows from operating activities
Net income (loss)	415	390
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	649	589
Deferred income taxes and amortization of investment tax credits	122	143
Other non-cash operating activities	(18)	23
Changes in assets and liabilities:
Accounts receivable	(163)	(48)
Receivables from payables to affiliates, net	(43)	5
Inventories	(2)	(2)
Accounts payable and accrued expenses	123	(45)
Collateral received (posted), net	60	2
Income taxes	(19)	(34)
Regulatory assets and liabilities, net	(267)	(181)
Pension and non-pension postretirement benefit contributions	(178)	(173)
Other assets and liabilities	(91)	(111)
Net Cash Provided by (Used in) Operating Activities, Total	588	558
Cash flows from investing activities
Capital expenditures	(1,208)	(1,162)
Other investing activities	15	12
Net Cash Provided by (Used in) Investing Activities, Total	(1,193)	(1,150)
Cash flows from financing activities
Changes in short-term borrowings	0	(290)
Issuance of long-term debt	750	700
Dividends paid on common stock	(289)	(253)
Contributions from parent	335	395
Other financing activities	(12)	(11)
Net cash flows provided by financing activities	784	541
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	179	(51)
Cash, restricted cash, and cash equivalents at beginning of period	384	405
Cash, restricted cash, and cash equivalents at end of period	563	354
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(44)	(93)
PECO Energy Co [Member]
Cash flows from operating activities
Net income (loss)	339	271
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	185	173
Deferred income taxes and amortization of investment tax credits	14	21
Other non-cash operating activities	4	(5)
Changes in assets and liabilities:
Accounts receivable	(29)	86
Receivables from payables to affiliates, net	(40)	2
Inventories	(8)	3
Accounts payable and accrued expenses	5	(46)
Income taxes	49	24
Regulatory assets and liabilities, net	(24)	(14)
Pension and non-pension postretirement benefit contributions	(13)	(15)
Other assets and liabilities	(70)	(126)
Net Cash Provided by (Used in) Operating Activities, Total	412	374
Cash flows from investing activities
Capital expenditures	(658)	(577)
Other investing activities	5	4
Net Cash Provided by (Used in) Investing Activities, Total	(653)	(573)
Cash flows from financing activities
Changes in short-term borrowings	210	0
Issuance of long-term debt	350	375
Retirement of long-term debt	(350)	0
Increase (Decrease) in Due to Affiliates, Current	0	(40)
Dividends paid on common stock	(200)	(169)
Contributions from parent	227	395
Other financing activities	(8)	(4)
Net cash flows provided by financing activities	229	557
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	(12)	358
Cash, restricted cash, and cash equivalents at beginning of period	44	26
Cash, restricted cash, and cash equivalents at end of period	32	384
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(11)	(16)
Baltimore Gas and Electric Company [Member]
Cash flows from operating activities
Net income (loss)	234	254
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	322	293
Deferred income taxes and amortization of investment tax credits	13	11
Other non-cash operating activities	79	28
Changes in assets and liabilities:
Accounts receivable	(14)	73
Receivables from payables to affiliates, net	(11)	(19)
Inventories	(27)	(9)
Accounts payable and accrued expenses	(12)	(51)
Collateral received (posted), net	190	2
Income taxes	(27)	(27)
Regulatory assets and liabilities, net	(36)	(61)
Pension and non-pension postretirement benefit contributions	(59)	(71)
Other assets and liabilities	24	(35)
Net Cash Provided by (Used in) Operating Activities, Total	676	388
Cash flows from investing activities
Capital expenditures	(578)	(620)
Other investing activities	7	10
Net Cash Provided by (Used in) Investing Activities, Total	(571)	(610)
Cash flows from financing activities
Changes in short-term borrowings	(130)	0
Issuance of long-term debt	500	600
Dividends paid on common stock	(150)	(146)
Contributions from parent	186	0
Other financing activities	(7)	(6)
Net cash flows provided by financing activities	399	448
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	504	226
Cash, restricted cash, and cash equivalents at beginning of period	55	145
Cash, restricted cash, and cash equivalents at end of period	559	371
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(21)	(71)
Pepco Holdings LLC [Member]
Cash flows from operating activities
Net income (loss)	230	269
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	459	404
Deferred income taxes and amortization of investment tax credits	(7)	10
Other non-cash operating activities	76	(50)
Changes in assets and liabilities:
Accounts receivable	(92)	(30)
Receivables from payables to affiliates, net	(53)	(22)
Inventories	(7)	3
Accounts payable and accrued expenses	10	(35)
Collateral received (posted), net	403	0
Income taxes	(2)	(1)
Regulatory assets and liabilities, net	(71)	(33)
Pension and non-pension postretirement benefit contributions	(70)	(40)
Other assets and liabilities	(86)	(98)
Net Cash Provided by (Used in) Operating Activities, Total	790	377
Cash flows from investing activities
Capital expenditures	(776)	(889)
Other investing activities	3	(2)
Net Cash Provided by (Used in) Investing Activities, Total	(773)	(891)
Cash flows from financing activities
Changes in short-term borrowings	(425)	(36)
Issuance of long-term debt	700	625
Retirement of long-term debt	(200)	(249)
Increase (Decrease) in Due to Affiliates, Current	17	(12)
Payments of Distributions to Affiliates	(395)	(414)
Proceeds from Contributions from Affiliates	704	560
Other financing activities	(12)	(8)
Net cash flows provided by financing activities	389	466
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	406	(48)
Cash, restricted cash, and cash equivalents at beginning of period	213	160
Cash, restricted cash, and cash equivalents at end of period	619	112
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(48)	(41)
Potomac Electric Power Company [Member]
Cash flows from operating activities
Net income (loss)	116	134
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	213	199
Deferred income taxes and amortization of investment tax credits	(7)	10
Other non-cash operating activities	17	(43)
Changes in assets and liabilities:
Accounts receivable	(62)	(23)
Receivables from payables to affiliates, net	(39)	(11)
Inventories	(6)	1
Accounts payable and accrued expenses	6	(26)
Collateral received (posted), net	85	0
Income taxes	(24)	(20)
Regulatory assets and liabilities, net	(36)	(38)
Pension and non-pension postretirement benefit contributions	(7)	(7)
Other assets and liabilities	(15)	(41)
Net Cash Provided by (Used in) Operating Activities, Total	241	135
Cash flows from investing activities
Capital expenditures	(402)	(439)
Other investing activities	2	(2)
Net Cash Provided by (Used in) Investing Activities, Total	(400)	(441)
Cash flows from financing activities
Changes in short-term borrowings	(132)	119
Issuance of long-term debt	400	150
Retirement of long-term debt	(200)	0
Increase (Decrease) in Due to Affiliates, Current	73	9
Dividends paid on common stock	(300)	(123)
Contributions from parent	387	138
Other financing activities	(6)	(2)
Net cash flows provided by financing activities	222	291
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	63	(15)
Cash, restricted cash, and cash equivalents at beginning of period	68	65
Cash, restricted cash, and cash equivalents at end of period	131	50
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(24)	(15)
Delmarva Power and Light Company [Member]
Cash flows from operating activities
Net income (loss)	77	86
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	113	104
Deferred income taxes and amortization of investment tax credits	3	4
Other non-cash operating activities	13	(12)
Changes in assets and liabilities:
Accounts receivable	(8)	24
Receivables from payables to affiliates, net	(3)	(12)
Inventories	1	0
Accounts payable and accrued expenses	12	7
Collateral received (posted), net	180	0
Income taxes	6	14
Regulatory assets and liabilities, net	(11)	(13)
Pension and non-pension postretirement benefit contributions	(1)	0
Other assets and liabilities	1	(9)
Net Cash Provided by (Used in) Operating Activities, Total	383	193
Cash flows from investing activities
Capital expenditures	(194)	(211)
Changes in Exelon/PHI intercompany money pool	(73)	(9)
Other investing activities	2	1
Net Cash Provided by (Used in) Investing Activities, Total	(265)	(219)
Cash flows from financing activities
Changes in short-term borrowings	(149)	(146)
Issuance of long-term debt	125	125
Dividends paid on common stock	(56)	(63)
Contributions from parent	144	120
Other financing activities	(4)	(3)
Net cash flows provided by financing activities	60	33
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	178	7
Cash, restricted cash, and cash equivalents at beginning of period	71	15
Cash, restricted cash, and cash equivalents at end of period	249	22
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	(5)	(14)
Atlantic City Electric Company [Member]
Cash flows from operating activities
Net income (loss)	37	51
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization, and accretion, including nuclear fuel and energy contract amortization	118	87
Deferred income taxes and amortization of investment tax credits	0	(2)
Other non-cash operating activities	25	(14)
Changes in assets and liabilities:
Accounts receivable	(20)	(30)
Receivables from payables to affiliates, net	(10)	4
Inventories	(2)	2
Accounts payable and accrued expenses	9	(2)
Collateral received (posted), net	137	0
Income taxes	8	2
Regulatory assets and liabilities, net	(11)	18
Pension and non-pension postretirement benefit contributions	(7)	(3)
Other assets and liabilities	(63)	(43)
Net Cash Provided by (Used in) Operating Activities, Total	221	70
Cash flows from investing activities
Capital expenditures	(179)	(239)
Net Cash Provided by (Used in) Investing Activities, Total	(179)	(239)
Cash flows from financing activities
Changes in short-term borrowings	(144)	(9)
Issuance of long-term debt	175	350
Retirement of long-term debt	0	(249)
Dividends paid on common stock	(38)	(229)
Contributions from parent	173	303
Other financing activities	(4)	(4)
Net cash flows provided by financing activities	162	162
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	204	(7)
Cash, restricted cash, and cash equivalents at beginning of period	29	30
Cash, restricted cash, and cash equivalents at end of period	233	23
Supplemental Cash Flow Information
Decrease in capital expenditures not paid	$ (19)	$ (13)