Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Amounts Attributable to Controlling Interests) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Organization And Basis Of Presentation [Line Items]
Income (Loss) from Continuing Operations	$ 491	$ 940	$ 604	$ 776	$ 98	$ 891	$ 726	$ 750	$ 2,811	$ 2,465	$ 2,590
Income (Loss) from Continuing Operations Attributable to Noncontrolling Interests									15	14	16
Income (Loss) from Continuing Operations Attributable to Parent									2,796	2,451	2,574
Income (Loss) From Discontinued Operations, net of tax	(9)	(5)	(57)	91	2	378	(113)	(843)	20	(576)	86
Loss from Discontinued Operations Attributable to Noncontrolling Interest, net of tax										(8)	(5)
(Loss) Income from Discontinued Operations Attributable to Parent, net of tax										(568)	91
Net income	482	935	547	867	100	1,269	613	(93)	2,831	1,889	2,676
Net Income Attributable to Noncontrolling Interest									15	6	11
Net Income (Loss) Attributable to Parent	477	932	543	864	97	1,274	609	(97)	2,816	1,883	2,665
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Income (Loss) from Continuing Operations	132	452	217	264	139	330	207	204	1,065	880	659
Income (Loss) from Continuing Operations Attributable to Noncontrolling Interests										5	3
Income (Loss) from Continuing Operations Attributable to Parent										875	656
Income (Loss) From Discontinued Operations, net of tax									(3)	(6)	16
(Loss) Income from Discontinued Operations Attributable to Parent, net of tax										(6)	16
Net income	131	451	217	263	139	330	202	203	1,062	874	675
Net Income Attributable to Noncontrolling Interest									11	5	3
Net Income (Loss) Attributable to Parent	$ 128	$ 448	$ 215	$ 260	$ 136	$ 329	$ 202	$ 202	$ 1,051	$ 869	$ 672