Fair Value Measurements and Credit Concentration (Nonrecurring Fair Value Measurements) (Details) (Nonrecurring [Member], Kerr Dam Project [Member], USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014
Nonrecurring Fair Value Measurements [Abstract]
Loss	$ 18	[1]
Carrying Amount [Member]
Nonrecurring Fair Value Measurements [Abstract]
Nonrecurring measurement asset value	47	[2]
Level 3 [Member]
Nonrecurring Fair Value Measurements [Abstract]
Nonrecurring measurement asset value	29
PPL Energy Supply LLC [Member]
Nonrecurring Fair Value Measurements [Abstract]
Loss	18	[1]
PPL Energy Supply LLC [Member] | Carrying Amount [Member]
Nonrecurring Fair Value Measurements [Abstract]
Nonrecurring measurement asset value	47	[2]
PPL Energy Supply LLC [Member] | Level 3 [Member]
Nonrecurring Fair Value Measurements [Abstract]
Nonrecurring measurement asset value	$ 29

[1] The loss on the Kerr Dam Project was recorded in the Supply segment and included in "Income (Loss) from Discontinued Operations (net of income taxes)" on PPL's and PPL Energy Supply's Statement of Income.

[2] Represents carrying value before fair value measurement.