Fair Value Of Financial Instruments (Gains And Losses On Fair Value Option Included In The Company's Consolidated Statements Of Operations) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accounts Notes And Loans Receivable [Line Items]
Net gains (losses) on financial instruments at fair value and foreign exchange	$ 5	$ 7	$ 62	$ (18)
Loan Repurchase Commitments [Member]
Accounts Notes And Loans Receivable [Line Items]
Net gains (losses) on financial instruments at fair value and foreign exchange	1	19	140	62
Fixed Maturity Securities Held At Fair Value [Member]
Accounts Notes And Loans Receivable [Line Items]
Net gains (losses) on financial instruments at fair value and foreign exchange	(37)	21	(35)	(36)
Residential Mortgage Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Net gains (losses) on financial instruments at fair value and foreign exchange	(87)	(4)	(16)	(103)
Other Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Net gains (losses) on financial instruments at fair value and foreign exchange	0	(7)	13	(48)
Other Assets [Member]
Accounts Notes And Loans Receivable [Line Items]
Net gains (losses) on financial instruments at fair value and foreign exchange	0	0	0	0
Long Term Debt [Member]
Accounts Notes And Loans Receivable [Line Items]
Net gains (losses) on financial instruments at fair value and foreign exchange	$ 164	$ 12	$ 85	$ 140