Employee Benefit Plans (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended																										12 Months Ended																									12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Duke Energy Carolinas [Member]	Dec. 31, 2011 Duke Energy Carolinas [Member]	Dec. 31, 2010 Duke Energy Carolinas [Member]	Dec. 31, 2012 Progress Energy [Member]	Dec. 31, 2011 Progress Energy [Member]	Dec. 31, 2010 Progress Energy [Member]	Dec. 31, 2012 Progress Energy Carolinas [Member]	Dec. 31, 2011 Progress Energy Carolinas [Member]	Dec. 31, 2010 Progress Energy Carolinas [Member]	Dec. 31, 2012 Progress Energy Florida [Member]	Dec. 31, 2011 Progress Energy Florida [Member]	Dec. 31, 2010 Progress Energy Florida [Member]	Dec. 31, 2012 Duke Energy Ohio [Member]	Dec. 31, 2011 Duke Energy Ohio [Member]	Dec. 31, 2010 Duke Energy Ohio [Member]	Dec. 31, 2012 Duke Energy Indiana [Member]	Dec. 31, 2011 Duke Energy Indiana [Member]	Dec. 31, 2010 Duke Energy Indiana [Member]	Dec. 31, 2012 Qualified Pension Plans [Member]	Dec. 31, 2011 Qualified Pension Plans [Member]	Dec. 31, 2010 Qualified Pension Plans [Member]	Dec. 31, 2012 Qualified Pension Plans [Member] Duke Energy Carolinas [Member]	Dec. 31, 2011 Qualified Pension Plans [Member] Duke Energy Carolinas [Member]	Dec. 31, 2011 Qualified Pension Plans [Member] Progress Energy [Member]	Dec. 31, 2010 Qualified Pension Plans [Member] Progress Energy [Member]	Dec. 31, 2012 Qualified Pension Plans [Member] Progress Energy [Member]	Dec. 31, 2012 Qualified Pension Plans [Member] Progress Energy Carolinas [Member]	Dec. 31, 2011 Qualified Pension Plans [Member] Progress Energy Carolinas [Member]	Dec. 31, 2012 Qualified Pension Plans [Member] Progress Energy Florida [Member]	Dec. 31, 2011 Qualified Pension Plans [Member] Progress Energy Florida [Member]	Dec. 31, 2012 Qualified Pension Plans [Member] Duke Energy Ohio [Member]	Dec. 31, 2011 Qualified Pension Plans [Member] Duke Energy Ohio [Member]	Dec. 31, 2012 Qualified Pension Plans [Member] Duke Energy Indiana [Member]	Dec. 31, 2011 Qualified Pension Plans [Member] Duke Energy Indiana [Member]	Dec. 31, 2012 Non-Qualified Pension Plans [Member]	Dec. 31, 2011 Non-Qualified Pension Plans [Member]	Dec. 31, 2012 Non-Qualified Pension Plans [Member] Duke Energy Carolinas [Member]	Dec. 31, 2011 Non-Qualified Pension Plans [Member] Duke Energy Carolinas [Member]	Dec. 31, 2012 Non-Qualified Pension Plans [Member] Progress Energy [Member]	Dec. 31, 2011 Non-Qualified Pension Plans [Member] Progress Energy [Member]	Dec. 31, 2012 Non-Qualified Pension Plans [Member] Progress Energy Carolinas [Member]	Dec. 31, 2011 Non-Qualified Pension Plans [Member] Progress Energy Carolinas [Member]	Dec. 31, 2012 Non-Qualified Pension Plans [Member] Progress Energy Florida [Member]	Dec. 31, 2011 Non-Qualified Pension Plans [Member] Progress Energy Florida [Member]	Dec. 31, 2012 Non-Qualified Pension Plans [Member] Duke Energy Ohio [Member]	Dec. 31, 2011 Non-Qualified Pension Plans [Member] Duke Energy Ohio [Member]	Dec. 31, 2012 Non-Qualified Pension Plans [Member] Duke Energy Indiana [Member]	Dec. 31, 2011 Non-Qualified Pension Plans [Member] Duke Energy Indiana [Member]	Dec. 31, 2012 Other Post-Retirement Benefit plans [Member]	Dec. 31, 2011 Other Post-Retirement Benefit plans [Member]	Dec. 31, 2012 Other Post-Retirement Benefit plans [Member] Duke Energy Carolinas [Member]	Dec. 31, 2011 Other Post-Retirement Benefit plans [Member] Duke Energy Carolinas [Member]	Dec. 31, 2012 Other Post-Retirement Benefit plans [Member] Progress Energy [Member]	Dec. 31, 2011 Other Post-Retirement Benefit plans [Member] Progress Energy [Member]		Dec. 31, 2010 Other Post-Retirement Benefit plans [Member] Progress Energy [Member]		Dec. 31, 2012 Other Post-Retirement Benefit plans [Member] Progress Energy Carolinas [Member]	Dec. 31, 2010 Other Post-Retirement Benefit plans [Member] Progress Energy Carolinas [Member]	Dec. 31, 2012 Other Post-Retirement Benefit plans [Member] Progress Energy Florida [Member]	Dec. 31, 2011 Other Post-Retirement Benefit plans [Member] Progress Energy Florida [Member]	Dec. 31, 2010 Other Post-Retirement Benefit plans [Member] Progress Energy Florida [Member]	Dec. 31, 2012 Other Post-Retirement Benefit plans [Member] Duke Energy Ohio [Member]	Dec. 31, 2011 Other Post-Retirement Benefit plans [Member] Duke Energy Ohio [Member]	Dec. 31, 2010 Other Post-Retirement Benefit plans [Member] Duke Energy Ohio [Member]	Dec. 31, 2012 Other Post-Retirement Benefit plans [Member] Duke Energy Indiana [Member]	Dec. 31, 2011 Other Post-Retirement Benefit plans [Member] Duke Energy Indiana [Member]	Dec. 31, 2010 Other Post-Retirement Benefit plans [Member] Duke Energy Indiana [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Qualified Pension Plans [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Qualified Pension Plans [Member] Duke Energy Carolinas [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Qualified Pension Plans [Member] Progress Energy [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Qualified Pension Plans [Member] Progress Energy Carolinas [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Qualified Pension Plans [Member] Progress Energy Florida [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Qualified Pension Plans [Member] Duke Energy Ohio [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Qualified Pension Plans [Member] Duke Energy Indiana [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Non-Qualified Pension Plans [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Non-Qualified Pension Plans [Member] Progress Energy [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Non-Qualified Pension Plans [Member] Progress Energy Carolinas [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Non-Qualified Pension Plans [Member] Progress Energy Florida [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Other Post-Retirement Benefit plans [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Other Post-Retirement Benefit plans [Member] Duke Energy Carolinas [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Other Post-Retirement Benefit plans [Member] Progress Energy [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Other Post-Retirement Benefit plans [Member] Progress Energy Carolinas [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Other Post-Retirement Benefit plans [Member] Progress Energy Florida [Member]	Dec. 31, 2013 Scenario, Forecast [Member] Other Post-Retirement Benefit plans [Member] Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized net actuarial loss																																																																								$ 216	$ 46	$ 101	$ 46	$ 49	$ 12	$ 23	$ 5	$ 4	$ 1	$ 1	$ 54	$ 3	$ 59	$ 37	$ 16	$ (1)
Unrecognized prior service cost																																																																								(12)	(6)	(4)	(1)	(2)	1	1	(1)	(1)			(15)	(7)	(4)	(2)	(1)
Accumulated other comprehensive loss	(306)	(234)		(16)	(19)		(67)	(165)		0	(71)		0	(27)		(1)	(28)		5	7
Accumulated benefit obligation																						7,843	4,661		2,028	1,787	2,692		2,820	1,264	1,263	1,261	1,142	501	602	653	582	332	151	16	17	175	162	36	33	44	42	4	4	5	5
Recognized subsidy receivable																																																				5	5	2	3	4					2		2						1	1
Defined contribution plan contribution by employer	$ 107	$ 86	$ 85	$ 37	$ 37	$ 36	$ 45	$ 44	$ 43	$ 24	$ 23	$ 23	$ 15	$ 14	$ 14	$ 4	$ 4	$ 4	$ 6	$ 8	$ 6
Expected long-term rate of return on plan assets																						8.00%	8.25%	8.50%			8.50%	8.75%																													5.00%	[1]	6.60%	[1]		8.75%	5.00%	5.00%	5.00%	8.00%	8.25%	8.50%	8.00%	8.25%	8.50%

[1] The weighted-average actuarial assumptions used by Progress Energy Carolinas and Progress Energy Florida were not materially different from the assumptions above, as applicable, with the exception of the expected long-term rate of return on plan assets which was 5.00% for all years presented for Progress Energy Florida and 8.75% in 2010 for Progress Energy Carolinas. Progress Energy Florida held no other post-retirement benefit plan assets as of December 31, 2012. Progress Energy Carolinas held no other post-retirement plan assets after December 31, 2010.