Employee Benefit Plans (Expected Benefit Payments) (Details) $ in Millions	Dec. 31, 2016 USD ($)
Qualified Pension Plans [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	$ 585
2018	595
2019	613
2020	632
2021	637
2022-2026	3,099
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	162
2018	171
2019	177
2020	186
2021	181
2022-2026	867
Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	159
2018	159
2019	164
2020	171
2021	175
2022-2026	890
Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	84
2018	83
2019	86
2020	90
2021	92
2022-2026	455
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	74
2018	75
2019	76
2020	79
2021	81
2022-2026	425
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	35
2018	33
2019	33
2020	34
2021	35
2022-2026	161
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	49
2018	49
2019	48
2020	47
2021	48
2022-2026	219
Non-Qualified Pension Plans [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	29
2018	25
2019	25
2020	24
2021	24
2022-2026	111
Non-Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	2
2018	2
2019	2
2020	2
2021	1
2022-2026	5
Non-Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	8
2018	8
2019	8
2020	8
2021	8
2022-2026	36
Non-Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	3
2018	3
2019	2
2020	2
2021	2
2022-2026	11
Non-Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	3
2018	3
2019	3
2020	3
2021	3
2022-2026	15
Non-Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2022-2026	1
Non-Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2022-2026	1
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	85
2018	81
2019	78
2020	75
2021	72
2022-2026	310
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	18
2018	18
2019	18
2020	18
2021	18
2022-2026	76
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	32
2018	31
2019	31
2020	30
2021	29
2022-2026	126
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	17
2018	16
2019	16
2020	16
2021	15
2022-2026	67
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	15
2018	15
2019	14
2020	14
2021	13
2022-2026	58
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	4
2018	3
2019	3
2020	3
2021	3
2022-2026	12
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2017	10
2018	9
2019	9
2020	8
2021	7
2022-2026	$ 31