For each line item in the statement of financial position, the amounts of gains and losses from fair value changes included in earnings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 30

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14172-108612

Name:	us-gaap_FairValueOptionChangesInFairValueGainLoss1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Fair Value Measurement - Nonrecurring Basis (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended								0 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Mar. 31, 2013 Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member]	Mar. 31, 2013 Fair Value, Measurements, Nonrecurring [Member] Level 2 [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Level 2 [Member]	Mar. 31, 2013 Fair Value, Measurements, Nonrecurring [Member] Level 3 [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Level 3 [Member]	Mar. 31, 2013 Residential Mortgage [Member] Fair Value, Measurements, Nonrecurring [Member] Level 3 [Member]	Dec. 31, 2012 Minimum Broker Price Opinion Valuation Technique [Member] Residential Mortgage [Member]	Dec. 31, 2012 Maximum Broker Price Opinion Valuation Technique [Member] Residential Mortgage [Member]	Dec. 31, 2012 Weighted Average [Member] Broker Price Opinion Valuation Technique [Member] Residential Mortgage [Member]
Assets and liabilities measured at fair value on a nonrecurring basis
Total assets at fair value on a nonrecurring basis			$ 1,000	$ 5,100	$ 176	$ 667	$ 800	$ 4,400	$ 733
Fair Value Inputs, Liquidation Value Discount										18.00%	59.00%	29.00%
Fair Value, Option, Changes in Fair Value, Gain (Loss)	$ (299)	$ 534