Asset Retirement Obligations (Narrative) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014		Dec. 31, 2013
Asset Retirement Obligations [Line Items]
Liabilities incurred in the current year	$ 3,433	[1]
Net property, plant and equipment	69,595		69,490
Regulatory assets, noncurrent	10,252		9,191
Regulatory liability, noncurrent	6,220		5,949
Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Liabilities incurred in the current year	2,026	[1]
Net property, plant and equipment	25,126		23,012
Regulatory assets, noncurrent	1,986		1,527
Regulatory liability, noncurrent	2,690		2,576
Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Liabilities incurred in the current year	1,406	[1]
Net property, plant and equipment	14,580		13,650
Regulatory assets, noncurrent	2,187		1,384
Regulatory liability, noncurrent	1,796		1,673
North Carolina Ash Basins [Member]
Asset Retirement Obligations [Line Items]
Number of Ash Basins	32
Number of Plants with Ash Basins	14
North Carolina Ash Basins [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Net property, plant and equipment	1,559
Regulatory assets, noncurrent	467
North Carolina Ash Basins [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Net property, plant and equipment	610
Regulatory assets, noncurrent	763
Removal Costs [Member] | North Carolina Ash Basins [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Regulatory liability, noncurrent	$ 33

[1] Amounts relate to asset obligations recorded in the third quarter of 2014 as a result of the Coal Ash Act and an agreement with the SCDHEC related to the W.S Lee Steam Station.