Supplemental Information About The Credit Quality Of Financing Receivables And Allowance For Losses On Financing Receivables (Real Estate) (Details) (Commercial Real Estate Portfolio Segment [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Financing Receivables And Allowance For Losses [Abstract]
Loans and leases receivable, Gross	$ 31,531		$ 32,749
General reserves	255		267
Total impaired loans	8,239		8,747
Allowance for losses (specific reserves)	674		822
Past Due Financing Receivables [Abstract]
Financing Receivable, Recorded Investment, Equal to Greater than 30 Days Past Due	3.10%		2.80%
Financing Receivable, Recorded Investments, Equal to Greater than 90 Days Past Due	2.50%		2.50%
Nonaccrual Financing Receivables [Abstract]
Nonaccrual loans	6,551		6,949
Nonearning financing receivables	761		790
Allowance for losses as a percent of nonaccrual financing receivables	14.20%		15.70%
Allowance for losses as a percent of nonearning financing receivables	122.10%		137.80%
Impaired Loans
Total impaired loans	8,239		8,747
Allowance for losses (specific reserves)	674		822
Average investment during the period	8,494		9,678
Interest income recognized	90	105	399
Interest income recognized on a cash basis	68	105	339
Financing Receivable, Modifications, Recorded Investment	6,606		7,006
Changes In Loans Modified As Troubled Debt Restructurings	1,067
Loans Modified As Troubled Debt Restructuring That Have Subsequently Experienced Payment Default	183
Credit Quality Indicators [Abstract]
Loans and leases receivable, Gross	31,531		32,749
Loan To Value Ratio Of Real Estate Loans Paying In Accordance With Contractual Terms	95.00%
Performing Financing Receivable [Member]
Financing Receivables And Allowance For Losses [Abstract]
Loans and leases receivable, Gross	23,292		24,002
Credit Quality Indicators [Abstract]
Loans and leases receivable, Gross	23,292		24,002
Impaired Financing Receivable with No Related Allowance [Member]
Financing Receivables And Allowance For Losses [Abstract]
Total impaired loans	3,953		3,790
Impaired Loans
Total impaired loans	3,953		3,790
Unpaid principal balance	4,004		3,846
Average investment during the period	3,872		3,783
Impaired Financing Receivable with Related Allowance [Member]
Financing Receivables And Allowance For Losses [Abstract]
Total impaired loans	4,286		4,957
Allowance for losses (specific reserves)	674		822
Impaired Loans
Total impaired loans	4,286		4,957
Unpaid principal balance	4,365		5,049
Allowance for losses (specific reserves)	674		822
Average investment during the period	4,622		5,895
Nonaccrual Financing Receivables [Member]
Nonaccrual Financing Receivables [Abstract]
Nonaccrual loans	6,551		6,949
Amount of nonaccrual loans currently paying in accordance with contractual terms	5,575		6,061
TDR Modifications [Member]
Impaired Loans
Financing Receivable, Modifications, Recorded Investment	3,107
Debt Real Estate [Member]
Financing Receivables And Allowance For Losses [Abstract]
Loans and leases receivable, Gross	23,518		24,501
Past Due Financing Receivables [Abstract]
Financing Receivable, Recorded Investment, Equal to Greater than 30 Days Past Due	2.80%		2.40%
Financing Receivable, Recorded Investments, Equal to Greater than 90 Days Past Due	2.30%		2.30%
Nonaccrual Financing Receivables [Abstract]
Nonaccrual loans	6,010		6,351
Nonearning financing receivables	522		541
Credit Quality Indicators [Abstract]
Loans and leases receivable, Gross	23,518		24,501
Debt Real Estate [Member] | Loan To Value Ratio Less Than 80 Percent [Member]
Financing Receivables And Allowance For Losses [Abstract]
Loans and leases receivable, Gross	14,041		14,454
Credit Quality Indicators [Abstract]
Loans and leases receivable, Gross	14,041		14,454
Debt Real Estate [Member] | Loan To Value Ratio From 80 To 95 Percent [Member]
Financing Receivables And Allowance For Losses [Abstract]
Loans and leases receivable, Gross	4,578		4,593
Credit Quality Indicators [Abstract]
Loans and leases receivable, Gross	4,578		4,593
Debt Real Estate [Member] | Loan To Value Ratio Greater Than 95 Percent [Member]
Financing Receivables And Allowance For Losses [Abstract]
Loans and leases receivable, Gross	4,899		5,454
Credit Quality Indicators [Abstract]
Loans and leases receivable, Gross	4,899		5,454
Debt Real Estate [Member] | Impaired Financing Receivable with No Related Allowance [Member]
Financing Receivables And Allowance For Losses [Abstract]
Total impaired loans	3,752		3,558
Impaired Loans
Total impaired loans	3,752		3,558
Unpaid principal balance	3,803		3,614
Average investment during the period	3,655		3,568
Debt Real Estate [Member] | Impaired Financing Receivable with Related Allowance [Member]
Financing Receivables And Allowance For Losses [Abstract]
Total impaired loans	3,914		4,560
Allowance for losses (specific reserves)	585		717
Impaired Loans
Total impaired loans	3,914		4,560
Unpaid principal balance	3,993		4,652
Allowance for losses (specific reserves)	585		717
Average investment during the period	4,237		5,435
Business Properties Real Estate [Member]
Financing Receivables And Allowance For Losses [Abstract]
Loans and leases receivable, Gross	8,013		8,248
Past Due Financing Receivables [Abstract]
Financing Receivable, Recorded Investment, Equal to Greater than 30 Days Past Due	3.70%		3.90%
Financing Receivable, Recorded Investments, Equal to Greater than 90 Days Past Due	3.00%		3.00%
Nonaccrual Financing Receivables [Abstract]
Nonaccrual loans	541		598
Nonearning financing receivables	239		249
Credit Quality Indicators [Abstract]
Loans and leases receivable, Gross	8,013		8,248
Business Properties Real Estate [Member] | Secured Credit Quality Indicator Low Risk [Member]
Financing Receivables And Allowance For Losses [Abstract]
Loans and leases receivable, Gross	7,489		7,628
Credit Quality Indicators [Abstract]
Loans and leases receivable, Gross	7,489		7,628
Business Properties Real Estate [Member] | Secured Credit Quality Indicator Moderate Risk [Member]
Financing Receivables And Allowance For Losses [Abstract]
Loans and leases receivable, Gross	102		110
Credit Quality Indicators [Abstract]
Loans and leases receivable, Gross	102		110
Business Properties Real Estate [Member] | Secured Credit Quality Indicator High Risk [Member]
Financing Receivables And Allowance For Losses [Abstract]
Loans and leases receivable, Gross	422		510
Credit Quality Indicators [Abstract]
Loans and leases receivable, Gross	422		510
Business Properties Real Estate [Member] | Impaired Financing Receivable with No Related Allowance [Member]
Financing Receivables And Allowance For Losses [Abstract]
Total impaired loans	201		232
Impaired Loans
Total impaired loans	201		232
Unpaid principal balance	201		232
Average investment during the period	217		215
Business Properties Real Estate [Member] | Impaired Financing Receivable with Related Allowance [Member]
Financing Receivables And Allowance For Losses [Abstract]
Total impaired loans	372		397
Allowance for losses (specific reserves)	89		105
Impaired Loans
Total impaired loans	372		397
Unpaid principal balance	372		397
Allowance for losses (specific reserves)	89		105
Average investment during the period	$ 385		$ 460