Contingencies and Other Matters - Legal and Regulatory Matters (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Mar. 31, 2013	Sep. 30, 2015	Sep. 30, 2014
Pending Litigation [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual, at Carrying Value		$ 190
Loss Contingency Accrual At Carrying Value, Net Of Tax		$ 125
Unfavorable Regulatory Action [Member]
Loss Contingencies [Line Items]
Monitoring period		2 years
Reassessment period		2 years
Reassessment Period, California		3 years
Loss Contingency Accrual, Carrying Value, Provision	$ 77
Loss Contingency Accrual Carrying Value, Provision, After Tax	$ 51
Insurance-related Assessments [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual, Carrying Value, Provision