Fair Value Measurements (Details 3) (USD $) In Millions	6 Months Ended
	Jun. 30, 2011	Dec. 31, 2010
Assets Measured at Fair Value on a Nonrecurring Basis
Impaired loans	$ 131	$ 219
Loans held for sale	25	15
Operating lease assets	0	0
Goodwill and other intangible assets	0	0
Accrued income and other assets	32	62
Other investments	1	0
Total assets on a nonrecurring basis at fair value	189	296
Additional Fair Value Measurements (Textuals)
Transfer of commercial and consumer loans from held-for-sale to held-to-maturity, current fair value	25
Average maturity of short term financial instrument	less than six months
Level 1 [Member]
Assets Measured at Fair Value on a Nonrecurring Basis
Impaired loans	0	0
Loans held for sale	0	0
Operating lease assets	0	0
Goodwill and other intangible assets	0	0
Accrued income and other assets	0	0
Other investments	0	0
Total assets on a nonrecurring basis at fair value	0	0
Level 2 [Member]
Assets Measured at Fair Value on a Nonrecurring Basis
Impaired loans	0	0
Loans held for sale	0	0
Operating lease assets	0	0
Goodwill and other intangible assets	0	0
Accrued income and other assets	19	39
Other investments	0	0
Total assets on a nonrecurring basis at fair value	19	39
Level 3 [Member]
Assets Measured at Fair Value on a Nonrecurring Basis
Impaired loans	131	219
Loans held for sale	25	15
Operating lease assets	0	0
Goodwill and other intangible assets	0	0
Accrued income and other assets	13	23
Other investments	1	0
Total assets on a nonrecurring basis at fair value	$ 170	$ 257