Leases (Lease Costs) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Operating lease expense	$ 292
Short-term lease expense	16
Variable lease expense	47
Finance lease expense
Amortization of leased assets	111
Interest on lease liabilities	61
Total finance lease expense	172
Total lease expense	527
Duke Energy Carolinas
Lessee, Lease, Description [Line Items]
Operating lease expense	47
Short-term lease expense	5
Variable lease expense	22
Finance lease expense
Amortization of leased assets	6
Interest on lease liabilities	15
Total finance lease expense	21
Total lease expense	95
Progress Energy
Lessee, Lease, Description [Line Items]
Operating lease expense	161
Short-term lease expense	9
Variable lease expense	22
Finance lease expense
Amortization of leased assets	21
Interest on lease liabilities	42
Total finance lease expense	63
Total lease expense	255
Duke Energy Progress
Lessee, Lease, Description [Line Items]
Operating lease expense	69
Short-term lease expense	4
Variable lease expense	16
Finance lease expense
Amortization of leased assets	5
Interest on lease liabilities	33
Total finance lease expense	38
Total lease expense	127
Duke Energy Florida
Lessee, Lease, Description [Line Items]
Operating lease expense	92
Short-term lease expense	5
Variable lease expense	6
Finance lease expense
Amortization of leased assets	16
Interest on lease liabilities	9
Total finance lease expense	25
Total lease expense	128
Duke Energy Ohio
Lessee, Lease, Description [Line Items]
Operating lease expense	11
Short-term lease expense	1
Finance lease expense
Amortization of leased assets	1
Total finance lease expense	1
Total lease expense	13
Duke Energy Indiana
Lessee, Lease, Description [Line Items]
Operating lease expense	20
Short-term lease expense	2
Variable lease expense	1
Finance lease expense
Interest on lease liabilities	1
Total finance lease expense	1
Total lease expense	24
Piedmont
Lessee, Lease, Description [Line Items]
Operating lease expense	5
Variable lease expense	1
Finance lease expense
Total lease expense	$ 6