Severance (Expenses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2013
2015 Severance Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	$ 142
2015 Severance Plan [Member] | Duke Energy Carolinas [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	93
2015 Severance Plan [Member] | Progress Energy [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	36
2015 Severance Plan [Member] | Duke Energy Progress [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	28
2015 Severance Plan [Member] | Duke Energy Florida [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	8
2015 Severance Plan [Member] | Duke Energy Ohio [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	2
2015 Severance Plan [Member] | Duke Energy Indiana [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	$ 6
Severance Plan 2011 [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense		$ 34
Accelerated stock compensation expense		5
COBRA and healthcare expense reimbursement		2
Severance Plan 2011 [Member] | Duke Energy Carolinas [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense		8
Severance Plan 2011 [Member] | Progress Energy [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense		19
Severance Plan 2011 [Member] | Duke Energy Progress [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense		14
Severance Plan 2011 [Member] | Duke Energy Florida [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense		5
Severance Plan 2011 [Member] | Duke Energy Ohio [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense		2
Severance Plan 2011 [Member] | Duke Energy Indiana [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense		$ 2