Asset Retirement Obligations (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Asset Retirement Obligation [Roll Forward]
Balance as of January 1	$ 5,176	[1]	$ 1,936
Acquisitions	4		3,062	[2]
Accretion expense	239	[3]	173	[3]
Liabilities settled	(12)		(15)
Revisions in estimates of cash flows	(449)	[4]	(4)
Liabilities incurred in the current year			24
Balance as of December 31	4,958	[1]	5,176	[1]
Duke Energy Carolinas [Member]
Asset Retirement Obligation [Roll Forward]
Balance as of January 1	1,959		1,846
Accretion expense	122	[3]	118	[3]
Liabilities settled			(3)
Revisions in estimates of cash flows	(487)	[4]	(2)
Balance as of December 31	1,594	[1]	1,959
Progress Energy [Member]
Asset Retirement Obligation [Roll Forward]
Balance as of January 1	2,420	[1]	1,265
Accretion expense	113	[3]	86	[3]
Liabilities settled	(12)		(2)
Revisions in estimates of cash flows	49		234	[5]
Liabilities incurred in the current year			837	[6]
Balance as of December 31	2,570	[1]	2,420	[1]
Duke Energy Progress [Member]
Asset Retirement Obligation [Roll Forward]
Balance as of January 1	1,656	[1]	896
Accretion expense	80	[3]	64	[3]
Liabilities settled			(2)
Revisions in estimates of cash flows	1
Liabilities incurred in the current year			698	[6]
Balance as of December 31	1,737	[1]	1,656	[1]
Asset retirement obligation, current	8		7
Duke Energy Florida [Member]
Asset Retirement Obligation [Roll Forward]
Balance as of January 1	764		369
Accretion expense	33	[3]	22	[3]
Liabilities settled	(12)
Revisions in estimates of cash flows	48	[4]	234	[5]
Liabilities incurred in the current year			139	[6]
Balance as of December 31	833	[1]	764
Duke Energy Ohio [Member]
Asset Retirement Obligation [Roll Forward]
Balance as of January 1	28		27
Accretion expense	2	[3]	1	[3]
Revisions in estimates of cash flows	(2)
Balance as of December 31	28	[1]	28
Duke Energy Indiana [Member]
Asset Retirement Obligation [Roll Forward]
Balance as of January 1	37		43
Accretion expense			1	[3]
Liabilities settled			(10)
Revisions in estimates of cash flows	(7)		(1)
Liabilities incurred in the current year			4
Balance as of December 31	$ 30	[1]	$ 37

[1] Balances at December 31, 2013 and 2012, include $8 million and $7 million, respectively, reported in Other current liabilities on the Consolidated Balance Sheets at Duke Energy, Progress Energy and Duke Energy Progress.

[2] Represents asset retirement obligations resulting from the merger with Progress Energy. See Note 2 for additional information.

[3] Substantially all accretion expense for the years ended December 31, 2013 and 2012 relates to Duke Energy’s regulated electric operations and has been deferred in accordance with regulatory accounting treatment.

[4] Amounts for Duke Energy, Duke Energy Carolinas and Duke Energy Florida primarily relate to the site-specific nuclear decommissioning cost studies completed in 2013.

[5] For Progress Energy and Duke Energy Florida, the amounts relate to the retirement of Crystal River Unit 3.

[6] For Progress Energy, Duke Energy Progress and Duke Energy Florida, amounts primarily relate to spent nuclear fuel disposal recorded in the third quarter of 2012 to conform to Duke Energy's assumptions for nuclear asset retirement obligations.