Leases (Supplemental Financial Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Assets
Operating lease right-of-use assets, net	$ 1,524	$ 1,658
Net property, plant and equipment	797	926
Total lease assets	2,321	2,584
Current
Operating	177	208
Finance	129	119
Noncurrent
Operating lease liabilities	1,340	1,432
Finance	716	850
Total lease liabilities	2,362	2,609
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	271	285
Operating cash flows from finance leases	61	61
Financing cash flows from finance leases	119	111
Lease assets obtained in exchange for new lease liabilities (non-cash)
Operating, lease assets obtained	116	194
Finance	$ 125	$ 251
Weighted-average remaining lease term (years)
Operating leases	10 years	11 years
Finance leases	13 years	13 years
Weighted-average discount rate
Operating leases	3.80%	3.90%
Finance leases	8.40%	8.10%
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PublicUtilitiesPropertyPlantAndEquipmentNet	us-gaap:PublicUtilitiesPropertyPlantAndEquipmentNet
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:DebtCurrent	us-gaap:DebtCurrent
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtNoncurrent	us-gaap:LongTermDebtNoncurrent
Duke Energy Carolinas
Assets
Operating lease right-of-use assets, net	$ 110	$ 123
Net property, plant and equipment	312	198
Total lease assets	422	321
Current
Operating	20	27
Finance	5	7
Noncurrent
Operating lease liabilities	97	102
Finance	289	172
Total lease liabilities	411	308
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	31	34
Operating cash flows from finance leases	30	15
Financing cash flows from finance leases	8	6
Lease assets obtained in exchange for new lease liabilities (non-cash)
Operating, lease assets obtained	17	44
Finance	$ 125	$ 76
Weighted-average remaining lease term (years)
Operating leases	9 years	9 years
Finance leases	19 years	19 years
Weighted-average discount rate
Operating leases	3.40%	3.50%
Finance leases	11.60%	11.80%
Progress Energy
Assets
Operating lease right-of-use assets, net	$ 690	$ 788
Net property, plant and equipment	416	443
Total lease assets	1,106	1,231
Current
Operating	73	95
Finance	26	24
Noncurrent
Operating lease liabilities	623	697
Finance	351	381
Total lease liabilities	1,073	1,197
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	124	131
Operating cash flows from finance leases	44	42
Financing cash flows from finance leases	$ 24	21
Lease assets obtained in exchange for new lease liabilities (non-cash)
Operating, lease assets obtained		30
Finance		$ 175
Weighted-average remaining lease term (years)
Operating leases	10 years	10 years
Finance leases	15 years	16 years
Weighted-average discount rate
Operating leases	3.80%	3.80%
Finance leases	11.90%	11.90%
Duke Energy Progress
Assets
Operating lease right-of-use assets, net	$ 346	$ 387
Net property, plant and equipment	297	308
Total lease assets	643	695
Current
Operating	31	37
Finance	7	6
Noncurrent
Operating lease liabilities	323	354
Finance	289	301
Total lease liabilities	650	698
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	52	53
Operating cash flows from finance leases	37	33
Financing cash flows from finance leases	$ 6	5
Lease assets obtained in exchange for new lease liabilities (non-cash)
Operating, lease assets obtained		30
Finance		$ 175
Weighted-average remaining lease term (years)
Operating leases	12 years	12 years
Finance leases	17 years	18 years
Weighted-average discount rate
Operating leases	3.90%	3.90%
Finance leases	12.40%	12.40%
Duke Energy Florida
Assets
Operating lease right-of-use assets, net	$ 344	$ 401
Net property, plant and equipment	119	135
Total lease assets	463	536
Current
Operating	42	58
Finance	19	18
Noncurrent
Operating lease liabilities	300	343
Finance	62	80
Total lease liabilities	423	499
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	72	78
Operating cash flows from finance leases	7	9
Financing cash flows from finance leases	$ 18	$ 16
Weighted-average remaining lease term (years)
Operating leases	8 years	8 years
Finance leases	11 years	11 years
Weighted-average discount rate
Operating leases	3.80%	3.80%
Finance leases	8.20%	8.30%
Duke Energy Ohio
Assets
Operating lease right-of-use assets, net	$ 20	$ 21
Total lease assets	20	21
Current
Operating	1	1
Noncurrent
Operating lease liabilities	20	21
Total lease liabilities	21	22
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	$ 2	2
Financing cash flows from finance leases		$ 1
Weighted-average remaining lease term (years)
Operating leases	17 years	17 years
Weighted-average discount rate
Operating leases	4.20%	4.20%
Finance leases	0.00%	0.00%
Duke Energy Indiana
Assets
Operating lease right-of-use assets, net	$ 55	$ 57
Net property, plant and equipment	7	7
Total lease assets	62	64
Current
Operating	3	3
Noncurrent
Operating lease liabilities	53	55
Finance	10	10
Total lease liabilities	66	68
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	6	7
Operating cash flows from finance leases		$ 1
Financing cash flows from finance leases	1
Lease assets obtained in exchange for new lease liabilities (non-cash)
Operating, lease assets obtained	$ 1
Weighted-average remaining lease term (years)
Operating leases	18 years	18 years
Finance leases	25 years	26 years
Weighted-average discount rate
Operating leases	4.20%	4.10%
Finance leases	11.90%	11.90%
Piedmont
Assets
Operating lease right-of-use assets, net	$ 20	$ 24
Total lease assets	20	24
Current
Operating	4	4
Noncurrent
Operating lease liabilities	19	23
Total lease liabilities	23	27
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	$ 5	7
Lease assets obtained in exchange for new lease liabilities (non-cash)
Operating, lease assets obtained		$ 1
Weighted-average remaining lease term (years)
Operating leases	5 years	6 years
Weighted-average discount rate
Operating leases	3.60%	3.60%
Finance leases	0.00%	0.00%