v3.26.3
Supplemental Financial Information - Cash Flow (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Depreciation, Amortization and Accretion [Abstract]        
Property, plant and equipment     $ 2,419 $ 2,270
Amortization of regulatory assets     491 444
Amortization of intangible assets, net     0 3
Accretion expense     2 2
Depreciation, amortization, and accretion     2,912 2,719
Other Non-Cash Operating Activities [Abstract]        
Pension and non-pension postretirement benefit costs     196 204
Allowance for credit losses     243 202
True-up adjustments to decoupling mechanisms and formula rates $ (35) $ (220) (138) (621)
Amortization of operating ROU asset     17 22
AFUDC - Equity (66) (49) (186) (130)
Other Non-Cash Activity        
Other Non-Cash Operating Activities [Abstract]        
True-up adjustments to decoupling mechanisms and formula rates     140 627
Return on borrowed funds        
Other Non-Cash Operating Activities [Abstract]        
AFUDC - Equity     (186) (130)
Commonwealth Edison Co        
Depreciation, Amortization and Accretion [Abstract]        
Property, plant and equipment     966 915
Amortization of regulatory assets     292 247
Amortization of intangible assets, net     0 0
Accretion expense     0 0
Depreciation, amortization, and accretion     1,258 1,162
Other Non-Cash Operating Activities [Abstract]        
Pension and non-pension postretirement benefit costs     80 64
Allowance for credit losses     62 41
True-up adjustments to decoupling mechanisms and formula rates (15) (206) (62) (525)
Amortization of operating ROU asset     0 0
AFUDC - Equity (25) (19) (71) (45)
Commonwealth Edison Co | Other Non-Cash Activity        
Other Non-Cash Operating Activities [Abstract]        
True-up adjustments to decoupling mechanisms and formula rates     62 525
Commonwealth Edison Co | Return on borrowed funds        
Other Non-Cash Operating Activities [Abstract]        
AFUDC - Equity     (71) (45)
PECO Energy Co        
Depreciation, Amortization and Accretion [Abstract]        
Property, plant and equipment     371 333
Amortization of regulatory assets     2 3
Amortization of intangible assets, net     0 0
Accretion expense     0 0
Depreciation, amortization, and accretion     373 336
Other Non-Cash Operating Activities [Abstract]        
Pension and non-pension postretirement benefit costs     13 5
Allowance for credit losses     70 75
True-up adjustments to decoupling mechanisms and formula rates 1 2 10 (6)
Amortization of operating ROU asset     0 0
AFUDC - Equity (12) (9) (33) (26)
PECO Energy Co | Other Non-Cash Activity        
Other Non-Cash Operating Activities [Abstract]        
True-up adjustments to decoupling mechanisms and formula rates     (10) 6
PECO Energy Co | Return on borrowed funds        
Other Non-Cash Operating Activities [Abstract]        
AFUDC - Equity     (33) (26)
Baltimore Gas and Electric Company        
Depreciation, Amortization and Accretion [Abstract]        
Property, plant and equipment     400 375
Amortization of regulatory assets     96 98
Amortization of intangible assets, net     0 0
Accretion expense     0 0
Depreciation, amortization, and accretion     496 473
Other Non-Cash Operating Activities [Abstract]        
Pension and non-pension postretirement benefit costs     21 46
Allowance for credit losses     51 20
True-up adjustments to decoupling mechanisms and formula rates (18) (20) (35) (63)
Amortization of operating ROU asset     5 5
AFUDC - Equity (17) (11) (47) (29)
Baltimore Gas and Electric Company | Other Non-Cash Activity        
Other Non-Cash Operating Activities [Abstract]        
True-up adjustments to decoupling mechanisms and formula rates     35 63
Baltimore Gas and Electric Company | Return on borrowed funds        
Other Non-Cash Operating Activities [Abstract]        
AFUDC - Equity     (47) (29)
Pepco Holdings LLC        
Depreciation, Amortization and Accretion [Abstract]        
Property, plant and equipment     640 606
Amortization of regulatory assets     101 95
Amortization of intangible assets, net     0 0
Accretion expense     0 2
Depreciation, amortization, and accretion     741 703
Other Non-Cash Operating Activities [Abstract]        
Pension and non-pension postretirement benefit costs     62 72
Allowance for credit losses     60 66
True-up adjustments to decoupling mechanisms and formula rates (3) 6 (51) (27)
Amortization of operating ROU asset     8 13
AFUDC - Equity (12) (10) (35) (30)
Pepco Holdings LLC | Other Non-Cash Activity        
Other Non-Cash Operating Activities [Abstract]        
True-up adjustments to decoupling mechanisms and formula rates     53 33
Pepco Holdings LLC | Return on borrowed funds        
Other Non-Cash Operating Activities [Abstract]        
AFUDC - Equity     (35) (30)
Potomac Electric Power Company        
Depreciation, Amortization and Accretion [Abstract]        
Property, plant and equipment     284 268
Amortization of regulatory assets     59 53
Amortization of intangible assets, net     0 0
Accretion expense     0 1
Depreciation, amortization, and accretion     343 322
Other Non-Cash Operating Activities [Abstract]        
Pension and non-pension postretirement benefit costs     23 26
Allowance for credit losses     28 29
True-up adjustments to decoupling mechanisms and formula rates 1 (5) (13) (19)
Amortization of operating ROU asset     2 4
AFUDC - Equity (9) (8) (27) (23)
Potomac Electric Power Company | Other Non-Cash Activity        
Other Non-Cash Operating Activities [Abstract]        
True-up adjustments to decoupling mechanisms and formula rates     13 19
Potomac Electric Power Company | Return on borrowed funds        
Other Non-Cash Operating Activities [Abstract]        
AFUDC - Equity     (27) (23)
Delmarva Power and Light Company        
Depreciation, Amortization and Accretion [Abstract]        
Property, plant and equipment     180 169
Amortization of regulatory assets     20 20
Amortization of intangible assets, net     0 0
Accretion expense     0 0
Depreciation, amortization, and accretion     200 189
Other Non-Cash Operating Activities [Abstract]        
Pension and non-pension postretirement benefit costs     11 12
Allowance for credit losses     12 13
True-up adjustments to decoupling mechanisms and formula rates (3) (5) (8) (10)
Amortization of operating ROU asset     3 4
AFUDC - Equity (2) (1) (5) (4)
Delmarva Power and Light Company | Other Non-Cash Activity        
Other Non-Cash Operating Activities [Abstract]        
True-up adjustments to decoupling mechanisms and formula rates     8 10
Delmarva Power and Light Company | Return on borrowed funds        
Other Non-Cash Operating Activities [Abstract]        
AFUDC - Equity     (5) (4)
Atlantic City Electric Company        
Depreciation, Amortization and Accretion [Abstract]        
Property, plant and equipment     173 166
Amortization of regulatory assets     22 22
Amortization of intangible assets, net     0 0
Accretion expense     0 0
Depreciation, amortization, and accretion     195 188
Other Non-Cash Operating Activities [Abstract]        
Pension and non-pension postretirement benefit costs     7 10
Allowance for credit losses     20 24
True-up adjustments to decoupling mechanisms and formula rates (1) 16 (30) 2
Amortization of operating ROU asset     1 2
AFUDC - Equity $ (1) $ (1) (3) (3)
Atlantic City Electric Company | Other Non-Cash Activity        
Other Non-Cash Operating Activities [Abstract]        
True-up adjustments to decoupling mechanisms and formula rates     32 4
Atlantic City Electric Company | Return on borrowed funds        
Other Non-Cash Operating Activities [Abstract]        
AFUDC - Equity     $ (3) $ (3)