Long-Term Debt Long-Term Debt - Coverage Ratio Requirements (Details) $ in Billions	12 Months Ended
	Dec. 31, 2016 USD ($)
2015 Credit Facilities
Debt Instrument [Line Items]
Covenant terms, minimum unrestricted liquidity, unrestricted cash, permitted investments and undrawn revolving credit facilities	$ 2.0
Covenant terms, minimum collateral coverage ratio	1.60
Pacific Facilities
Debt Instrument [Line Items]
Covenant terms, minimum fixed charge coverage ratio	1.20
Covenant terms, minimum unrestricted liquidity, unrestricted cash, permitted investments and undrawn revolving credit facilities	$ 2.0
Covenant terms, minimum collateral coverage ratio	1.60