Commitments, Contingencies and Guarantees (Narrative) (Details) (USD $)
Mar. 31, 2015
ATM Guarantee [Member] | Citishare Network Guarantee [Member]  
Commitments, Contingencies and Guarantees [Line Items]  
Maximum potential future payment $ 15,000,000
Commitments to Extend Credit [Member]  
Commitments, Contingencies and Guarantees [Line Items]  
Unused commitments to extend credit for loans $ 174,000,000,000