Derivative Instruments Additional Information (Detail) € in Millions, MW in Millions, $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($) MW	Mar. 31, 2015 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 EUR (€) MW	Dec. 31, 2015 USD ($)
Derivative [Line Items]
Proceeds from Hedge, Investing Activities		$ 2
Proceeds from Hedge, Investing Activities		14	$ 3
Payments for (Proceeds from) Hedge, Investing Activities		0	$ (7)
Line of Credit Facility, Maximum Borrowing Capacity		1,200
Liabilities, Current		358				$ 371
Currency Swap [Member]
Derivative [Line Items]
Derivative Asset, Current		1
Senior Loans [Member] | Term Loan [Member] | Dublin EfW Facility [Member]
Derivative [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity | €					€ 250
Energy Hedges [Member]
Derivative [Line Items]
Derivative Asset, Current		17
Derivative Asset		22
Derivative Asset, Noncurrent		5
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability		22
Liabilities, Current		2
Liabilities, Noncurrent		$ 20
Fiscal Year 2016 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MW		1.8			1.8
Fiscal Year 2017 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MW		1.6			1.6
Fiscal Year 2018 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MW		0.1			0.1
Sanfeng Environmental [Member] | Scenario, Forecast [Member]
Derivative [Line Items]
Proceeds from Sale of Other Investments	$ 100			$ 105