Commitments and Contingencies - Environmental Matters (Details) $ in Millions	9 Months Ended
	Sep. 30, 2015 USD ($) other_criteria_pollutant Method
Environmental Matters
Accrued environmental remediation costs	$ 1
Maximum exposure	$ 1
Number of estimation methodologies | Method	2
Climate Change and Other Emissions
Environmental Matters
Number of major sources of other "criteria" pollutant | other_criteria_pollutant	6
Maximum | Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) Matters
Environmental Matters
Accrued environmental remediation costs	$ 1