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	Jun. 30, 2014	Dec. 31, 2013
Non Variable Interest Entity [Member]
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items]
Medium-term notes, contractual outstanding principal	$ 274	$ 276
Medium-term notes, fair value	217	203
Medium-term notes, difference	57	73
Variable Interest Entity [Member]
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items]
Loans receivable, contractual outstanding principal	1,972	2,077
Variable interest entity notes, contractual outstanding principal	3,428	3,787
Loans receivable, fair value	1,539	1,612
Variable interest entity notes, fair value	2,150	2,356
Loans receivable, difference	433	465
Variable interest entity notes, difference	1,278	1,431
Residential Mortgage Loans [Member] | Variable Interest Entity [Member]
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items]
Loans receivable, contractual outstanding principal	1,729	1,846
Loans receivable, 90 days or more past due, contractual outstanding principal	243	231
Loans receivable, fair value	1,510	1,562
Loans receivable, 90 days or more past due, fair value	29	50
Loans receivable, difference	219	284
Loans receivable, 90 days or more past due, difference	214	181
Other Loans [Member] | Variable Interest Entity [Member]
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items]
Loans receivable, contractual outstanding principal	0	0
Loans receivable, 90 days or more past due, contractual outstanding principal	0	0
Loans receivable, fair value	0	0
Loans receivable, 90 days or more past due, fair value	0	0
Loans receivable, difference	0	0
Loans receivable, 90 days or more past due, difference	$ 0	$ 0