Severance (Expenses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
2016 Severance Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	$ 118
2016 Severance Plan [Member] | Duke Energy Carolinas [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	39
2016 Severance Plan [Member] | Progress Energy [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	40
2016 Severance Plan [Member] | Duke Energy Progress [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	23
2016 Severance Plan [Member] | Duke Energy Florida [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	17
2016 Severance Plan [Member] | Duke Energy Ohio [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	3
2016 Severance Plan [Member] | Duke Energy Indiana [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	$ 7
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