Leases (Supplemental Financial Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Jan. 01, 2019
Assets
ROU assets	$ 1,658	$ 1,750
Finance	926
Total lease assets	2,584
Current
Operating	208	205
Finance	119
Noncurrent
Operating lease liabilities	1,432	1,504
Finance	850
Total lease liabilities	2,609
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	285
Operating cash flows from finance leases	61
Financing cash flows from finance leases	111
Lease assets obtained in exchange for new lease liabilities (non-cash)
Operating, lease assets obtained	194
Finance	$ 251
Weighted-average remaining lease term (years)
Operating leases	11 years
Finance leases	13 years
Weighted-average discount rate
Operating leases	3.90%
Finance leases	8.10%
Duke Energy Carolinas
Assets
ROU assets	$ 123	153
Finance	198
Total lease assets	321
Current
Operating	27	28
Finance	7
Noncurrent
Operating lease liabilities	102	127
Finance	172
Total lease liabilities	308
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	34
Operating cash flows from finance leases	15
Financing cash flows from finance leases	6
Lease assets obtained in exchange for new lease liabilities (non-cash)
Operating, lease assets obtained	44
Finance	$ 76
Weighted-average remaining lease term (years)
Operating leases	9 years
Finance leases	19 years
Weighted-average discount rate
Operating leases	3.50%
Finance leases	11.80%
Progress Energy
Assets
ROU assets	$ 788	863
Finance	443
Total lease assets	1,231
Current
Operating	95	96
Finance	24
Noncurrent
Operating lease liabilities	697	766
Finance	381
Total lease liabilities	1,197
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	131
Operating cash flows from finance leases	42
Financing cash flows from finance leases	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
Finance leases	16 years
Weighted-average discount rate
Operating leases	3.80%
Finance leases	11.90%
Duke Energy Progress
Assets
ROU assets	$ 387	407
Finance	308
Total lease assets	695
Current
Operating	37	35
Finance	6
Noncurrent
Operating lease liabilities	354	371
Finance	301
Total lease liabilities	698
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	53
Operating cash flows from finance leases	33
Financing cash flows from finance leases	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
Finance leases	18 years
Weighted-average discount rate
Operating leases	3.90%
Finance leases	12.40%
Duke Energy Florida
Assets
ROU assets	$ 401	456
Finance	135
Total lease assets	536
Current
Operating	58	61
Finance	18
Noncurrent
Operating lease liabilities	343	395
Finance	80
Total lease liabilities	499
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	78
Operating cash flows from finance leases	9
Financing cash flows from finance leases	$ 16
Weighted-average remaining lease term (years)
Operating leases	8 years
Finance leases	11 years
Weighted-average discount rate
Operating leases	3.80%
Finance leases	8.30%
Duke Energy Ohio
Assets
ROU assets	$ 21	23
Total lease assets	21
Current
Operating	1	1
Noncurrent
Operating lease liabilities	21	22
Total lease liabilities	22
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	2
Financing cash flows from finance leases	$ 1
Weighted-average remaining lease term (years)
Operating leases	17 years
Weighted-average discount rate
Operating leases	4.20%
Finance leases	0.00%
Duke Energy Indiana
Assets
ROU assets	$ 57	61
Finance	7
Total lease assets	64
Current
Operating	3	4
Noncurrent
Operating lease liabilities	55	58
Finance	10
Total lease liabilities	68
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	7
Operating cash flows from finance leases	$ 1
Weighted-average remaining lease term (years)
Operating leases	18 years
Finance leases	26 years
Weighted-average discount rate
Operating leases	4.10%
Finance leases	11.90%
Piedmont
Assets
ROU assets	$ 24	26
Total lease assets	24
Current
Operating	4	4
Noncurrent
Operating lease liabilities	23	$ 25
Total lease liabilities	27
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	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	6 years
Weighted-average discount rate
Operating leases	3.60%
Finance leases	0.00%