Impairments (Details) - USD ($)		3 Months Ended			6 Months Ended
	May 13, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Jul. 14, 2017	May 12, 2016
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment losses		$ 63,000,000	$ 56,000,000		$ 63,000,000	$ 56,000,000
Construction in progress		0			$ 0
Impairment loss on investment						$ 139,000,000
Petra Nova Parish Holdings
Impaired Long-Lived Assets Held and Used [Line Items]
Ownership percentage				50.00%
Impairment loss on investment				$ 140,000,000
Other Intangible Assets
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment losses			8,000,000
Deferred Marketing Expenses
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment losses			10,000,000
Rockford
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment losses			17,000,000
Percentage of ownership								100.00%
Proceeds from sale of property, plant, and equipment	$ 55,000,000
Renewables
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment losses		22,000,000
Subsequent Event | Collectibility of receivables | BTEC New Albany, LLC
Impaired Long-Lived Assets Held and Used [Line Items]
Amount owed from BTEC New Albany, LLC							$ 48,000,000
Subsequent Event | Collectibility of receivables | Purchaser incurred costs | BTEC New Albany, LLC
Impaired Long-Lived Assets Held and Used [Line Items]
Amount owed from BTEC New Albany, LLC							38,000,000
Subsequent Event | Collectibility of receivables | Liquidation damages | BTEC New Albany, LLC
Impaired Long-Lived Assets Held and Used [Line Items]
Amount owed from BTEC New Albany, LLC							$ 10,000,000
Construction in Progress
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment losses		$ 41,000,000
Solar Panels
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment losses			$ 17,000,000