Contingencies, Commitments and Guarantees (Insolvency Assessments) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Other Assets:
Premium tax offset for future undiscounted assessments	$ 34	$ 46
Premium tax offsets currently available for paid assessments	65	54
Other Liabilities:
Insolvency assessments	50	67
Insurance-related Assessments [Member]
Loss Contingencies [Line Items]
Total assets held for insolvency assessments	$ 99	$ 100