Employee Benefit Plans (Expected Benefit Payments) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Qualified Pension Plans [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	$ 816
2014	653
2015	639
2016	636
2017	627
2018-2022	2,997
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	250
2014	214
2015	210
2016	207
2017	199
2018-2022	868
Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	217
2014	194
2015	193
2016	196
2017	197
2018-2022	978
Qualified Pension Plans [Member] | Progress Energy Carolinas [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	122
2014	105
2015	101
2016	100
2017	98
2018-2022	442
Qualified Pension Plans [Member] | Progress Energy Florida [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	71
2014	68
2015	71
2016	74
2017	78
2018-2022	431
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	36
2014	35
2015	35
2016	35
2017	35
2018-2022	186
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	48
2014	47
2015	46
2016	46
2017	45
2018-2022	231
Non-Qualified Pension Plans [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	31
2014	31
2015	28
2016	27
2017	28
2018-2022	120
Non-Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	3
2014	2
2015	2
2016	2
2017	2
2018-2022	6
Non-Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	12
2014	12
2015	12
2016	11
2017	11
2018-2022	56
Non-Qualified Pension Plans [Member] | Progress Energy Carolinas [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	2
2014	2
2015	2
2016	2
2017	2
2018-2022	11
Non-Qualified Pension Plans [Member] | Progress Energy Florida [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	3
2014	3
2015	3
2016	3
2017	3
2018-2022	15
Non-Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2018-2022	2
Non-Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2018-2022	2
Other Post-Retirement Benefit plans [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	98	[1]
2014	104	[1]
2015	108	[1]
2016	111	[1]
2017	114	[1]
2018-2022	583	[1]
Prescription Drug Subsidy Receipts, Fiscal Year Maturity [Abstract]
Subsidy 2013	7
Subsidy 2014	7
Subsidy 2015	7
Subsidy 2016	8
Subsidy 2017	8
Subsidy 2018 - 2022	46
Other Post-Retirement Benefit plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	22	[2]
2014	23	[2]
2015	23	[2]
2016	24	[2]
2017	24	[2]
2018-2022	112	[2]
Prescription Drug Subsidy Receipts, Fiscal Year Maturity [Abstract]
Subsidy 2013	2
Subsidy 2014	2
Subsidy 2015	2
Subsidy 2016	2
Subsidy 2017	2
Subsidy 2018 - 2022	8
Other Post-Retirement Benefit plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	48	[3]
2014	51	[3]
2015	55	[3]
2016	58	[3]
2017	61	[3]
2018-2022	330	[3]
Prescription Drug Subsidy Receipts, Fiscal Year Maturity [Abstract]
Subsidy 2013	4
Subsidy 2014	4
Subsidy 2015	4
Subsidy 2016	5
Subsidy 2017	5
Subsidy 2018 - 2022	34
Other Post-Retirement Benefit plans [Member] | Progress Energy Carolinas [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	24	[4]
2014	26	[4]
2015	28	[4]
2016	30	[4]
2017	32	[4]
2018-2022	177	[4]
Prescription Drug Subsidy Receipts, Fiscal Year Maturity [Abstract]
Subsidy 2013	2
Subsidy 2014	2
Subsidy 2015	2
Subsidy 2016	3
Subsidy 2017	3
Subsidy 2018 - 2022	19
Other Post-Retirement Benefit plans [Member] | Progress Energy Florida [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	20	[5]
2014	21	[5]
2015	22	[5]
2016	23	[5]
2017	24	[5]
2018-2022	125	[5]
Prescription Drug Subsidy Receipts, Fiscal Year Maturity [Abstract]
Subsidy 2013	2
Subsidy 2014	2
Subsidy 2015	2
Subsidy 2016	2
Subsidy 2017	2
Subsidy 2018 - 2022	12
Other Post-Retirement Benefit plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	4	[6]
2014	4	[6]
2015	4	[6]
2016	4	[6]
2017	4	[6]
2018-2022	19	[6]
Other Post-Retirement Benefit plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	12	[7]
2014	12	[7]
2015	12	[7]
2016	12	[7]
2017	12	[7]
2018-2022	53	[7]
Prescription Drug Subsidy Receipts, Fiscal Year Maturity [Abstract]
Subsidy 2013	1
Subsidy 2014	1
Subsidy 2015	1
Subsidy 2016	1
Subsidy 2017	1
Subsidy 2018 - 2022	$ 5

[1] Duke Energy expects to receive future subsidies under Medicare Part D of $7 million in each of the years 2013-2015, $8 million in each of the years 2016 and 2017, and a total of $46 million during the years 2018-2022.

[2] Duke Energy Carolinas expects to receive future subsidies under Medicare Part D of $2 million in each of the years 2013-2017 and a total of $8 million during the years 2018-2022.

[3] Progress Energy expects to receive future subsidies under Medicare Part D of $4 million in each of the years 2013-2015, $5 million each of the years 2016-2017, and a total of $34 million during the years 2018-2022.

[4] Progress Energy Carolinas expects to receive future subsidies under Medicare Part D of $2 million in each of the years 2013-2015, $3 million in each of the years 2016-2017, and a total of $19 million during the years 2018-2022.

[5] Progress Energy Florida expects to receive future subsidies under Medicare Part D of $2 million in each of the years 2013-2017, and a total of $12 million during the years 2018-2022.

[6] Duke Energy Ohio does not expect to receive future subsidies under Medicare Part D.

[7] Duke Energy Indiana expects to receive future subsidies under Medicare Part D of $1 million in each of the years 2013-2017 and a total of $5 million during the years 2018-2022.