Amortized Cost and Fair Value of Available-for-Sale and Held-to-Maturity Securities (Detail) (USD $) In Millions	Jun. 30, 2011		Dec. 31, 2010		Jun. 30, 2010
Debt securities:
Under 1 year	$ 508	[1]
1-5 years	8,611	[1]
5-10 years	4,528	[1]
Over 10 years	210	[1]
Other securities	1,032	[1]
Total	14,889	[1]	14,919		15,356
Debt securities:
Under 1 year	517	[1]
1-5 years	9,041	[1]
5-10 years	4,694	[1]
Over 10 years	214	[1]
Other securities	1,036	[1]
Fair Value	15,502	[1],[2]	15,414	[2]	16,021	[2]
Debt securities:
Under 1 year	29	[1]
1-5 years	242	[1]
5-10 years	50	[1]
Over 10 years	23	[1]
Other securities		[1]
Total	344	[1],[3]	353	[3]	354	[3]
Debt securities:
Under 1 year	29	[1]
1-5 years	242	[1]
5-10 years	50	[1]
Over 10 years	23	[1]
Other securities		[1]
Fair Value	$ 344	[1]	$ 353		$ 354

[1] Actual maturities may differ from contractual maturities when there exists a right to call or prepay obligations with or without call or prepayment penalties.

[2] Amortized cost of $14,889, $14,919 and $15,356 at June 30, 2011, December 31, 2010 and June 30, 2010, respectively.

[3] Fair value of $344, $353 and $354 at June 30, 2011, December 31, 2010 and June 30, 2010, respectively.