Commitments And Contingencies Unsecured Creditors Litigation (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loss Contingencies [Line Items]
Reserve for Unsecured Creditors Litigation	$ 300,000,000	$ 300,000,000	$ 0
Loss Contingency Accrual, Provision		300,000,000	$ 0	$ 0
Unsecured Creditors Litigation
Loss Contingencies [Line Items]
Loss Contingency, Damages Sought, Value Per Unit in Excess of Benchmark		32.50
Loss Contingency, Damages Sought, Unit in Excess of Benchmark		67.50
Judicial Ruling | Unsecured Creditors Litigation
Loss Contingencies [Line Items]
Reserve for Unsecured Creditors Litigation	300,000,000	$ 300,000,000
Per share loss contingency accrual provision		$ 1.10
Litigation, Damages Benchmark, Fourth LLP Agreement | Unsecured Creditors Litigation
Loss Contingencies [Line Items]
Cumulative Distributions Threshold		$ 7,200,000,000
Other income (expense), net | Judicial Ruling | Unsecured Creditors Litigation
Loss Contingencies [Line Items]
Loss Contingency Accrual, Provision	$ 300,000,000