Asset Impairment Expense (Tables)

12 Months Ended

Dec. 31, 2018

Impairment or Disposal of Tangible Assets Disclosure [Abstract]

Details of Impairment of Long-Lived Assets Held and Used by Asset

Year ended December 31, (in millions)	2018		2017		2016
Shady Point	$	157	$	—	$	—
Nejapa	37		—		—
DPL	—		175		859
Laurel Mountain	—		121		—
Kazakhstan Hydroelectric	—		92		—
Kazakhstan CHPs	—		94		—
Kilroot	—		37		—
Buffalo Gap II	—		—		159
Buffalo Gap I	—		—		77
Other	14		18		1
Total	$	208	$	537	$	1,096