Derivative Financial Instruments (Narrative) (Details) (USD $)	3 Months Ended							3 Months Ended	12 Months Ended
	Mar. 31, 2014		Mar. 31, 2013	Dec. 31, 2013		Mar. 31, 2014 Fair Value Hedges 1.35% Senior Note	Mar. 31, 2014 Fair Value Hedges 3.70% senior notes due in 2023	Mar. 31, 2014 Cash Flow Hedges	Dec. 31, 2013 Cash Flow Hedges	Mar. 31, 2014 Credit swap agreements	Mar. 31, 2014 Interest rate swap Fair Value Hedges 3.1% Subordinated Note	Mar. 31, 2014 Interest rate swap Fair Value Hedges Senior notes security	Mar. 31, 2014 Interest rate swap Fair Value Hedges Subordinated note security
Derivative [Line Items]
Cash collateral received for derivative instruments	$ 1,740,000,000			$ 2,580,000,000
Cash collateral provided for derivative instruments	2,460,000,000			3,360,000,000
Fair value of derivative liabilities	8,121,000,000	[1]		11,811,000,000	[1]					422,000,000
Maximum additional amount of payments related to termination events										$ 422,000,000
Weighted average life of trusts (in years)	6 years 3 months 15 days		6 years 6 months
Number of securities												2	1
Fixed interest rate						1.35%	3.70%				3.10%
Securities weighted average life (in years)								7 months	10 months

[1] Amounts include all transactions regardless of whether or not they are subject to an enforceable netting arrangement.