Schedule I - Condensed Parent Company Financial Statements (Annual Maturities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Condensed Financial Statements, Captions
2013	$ 3,098	[1]
2014	2,196	[1]
2015	2,478	[1]
2016	2,184	[1]
2017	1,321	[1]
Thereafter	25,873	[1]
Total long-term debt, including current maturities	39,461		20,573
Parent Company [Member]
Condensed Financial Statements, Captions
2013	706
2014	1,249
2015	449
2016	499
2017	699
Thereafter	2,009
Total long-term debt, including current maturities	$ 5,611

[1] At December 31, 2012, capital leases of Duke Energy included $158 million and $907 million of capital lease purchase accounting adjustments for Progress Energy Carolinas and Progress Energy Florida, respectively, related to power purchase agreements that are not accounted for as leases on their financial statements because of grandfathering provisions in GAAP.