Employee Benefit Plans (Employee Savings Plans) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Employee Savings Plans [Abstract]
Pretax employer matching contributions	$ 36	$ 30	$ 80	$ 71
Duke Energy Carolinas [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	12	10	26	24
Progress Energy [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	11	10	23	22
Duke Energy Progress [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	7	6	16	12
Duke Energy Florida [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	3	3	7	7
Duke Energy Ohio [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	1	1	2	2
Duke Energy Indiana [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	$ 2	$ 1	$ 4	$ 3