Business Developments And Risks And Uncertainties (Assets And Liabilities Held For Sale) (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Assets And Liabilities Held For Sale By Major Category [Line Items]
Assets held for sale	$ 22	$ 802
Liabilities held for sale	0	772
Investments At Fair Value [Member]
Assets And Liabilities Held For Sale By Major Category [Line Items]
Assets held for sale	0	6
Cash And Cash Equivalents [Member]
Assets And Liabilities Held For Sale By Major Category [Line Items]
Assets held for sale	0	15
Facility [Member]
Assets And Liabilities Held For Sale By Major Category [Line Items]
Assets held for sale	22	26
Other Assets [Member]
Assets And Liabilities Held For Sale By Major Category [Line Items]
Assets held for sale	0	4
Cash [Member]
Assets And Liabilities Held For Sale By Major Category [Line Items]
Assets held for sale	0	40
Loans Receivable [Member]
Assets And Liabilities Held For Sale By Major Category [Line Items]
Assets held for sale	0	711
Other Liabilities [Member]
Assets And Liabilities Held For Sale By Major Category [Line Items]
Liabilities held for sale	0	18
Variable Interest Entities Notes [Member]
Assets And Liabilities Held For Sale By Major Category [Line Items]
Liabilities held for sale	0	431
Payable For Loans Purchased [Member]
Assets And Liabilities Held For Sale By Major Category [Line Items]
Liabilities held for sale	$ 0	$ 323