Contingencies and Other Matters - Legal and Regulatory Matters (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2013
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