Fair Value Of Financial Instruments (Aggregate Fair Value And Remaining Contractual Principal Balance Outstanding On Fair Value Option) (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items]
Loans receivable, Contractual Outstanding Principal	$ 2,153	$ 2,770
Variable interest entity notes, Contractual Outstanding Principal	3,859	9,021
Loans receivable, Fair Value	1,704	1,881
Variable interest entity notes, Fair Value	2,426	3,659
Loans receivable, Difference	449	889
Variable interest entity notes, Difference	1,433	5,362
Residential Mortgage Loans [Member]
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items]
Loans receivable, Contractual Outstanding Principal	1,932	2,307
Loans receivable, 90 days or more past due, Contractual Outstanding Principal	221	244
Loans receivable, Fair Value	1,622	1,735
Loans receivable, 90 days or more past due, Fair Value	82	54
Loans receivable, Difference	310	572
Loans receivable, 90 days or more past due, Difference	139	190
Other Loans [Member]
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items]
Loans receivable, Contractual Outstanding Principal	0	22
Loans receivable, 90 days or more past due, Contractual Outstanding Principal	0	197
Loans receivable, Fair Value	0	22
Loans receivable, 90 days or more past due, Fair Value	0	70
Loans receivable, Difference	0	0
Loans receivable, 90 days or more past due, Difference	$ 0	$ 127