Derivatives and Hedging Activities (Schedule of Fair Value and Outstanding Notional Amounts of Derivative Instruments and Related Collateral Balances) (Details)
In Millions, unless otherwise specified
Mar. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Mar. 31, 2015
Designated as Hedges [Member]
Cash Flow Hedge [Member]
Interest Rate Swaps [Member]
USD ($)
transactions
Dec. 31, 2014
Designated as Hedges [Member]
Cash Flow Hedge [Member]
Interest Rate Swaps [Member]
USD ($)
Mar. 31, 2015
Designated as Hedges [Member]
Fair Value Hedge [Member]
Interest Rate Swaps [Member]
USD ($)
transactions
Dec. 31, 2014
Designated as Hedges [Member]
Fair Value Hedge [Member]
Interest Rate Swaps [Member]
USD ($)
Mar. 31, 2015
Designated as Hedges [Member]
Net Investment Hedge [Member]
Foreign Exchange Forward Contracts [Member]
USD ($)
transactions
Mar. 31, 2015
Designated as Hedges [Member]
Net Investment Hedge [Member]
Foreign Exchange Forward Contracts [Member]
EUR (€)
Dec. 31, 2014
Designated as Hedges [Member]
Net Investment Hedge [Member]
Foreign Exchange Forward Contracts [Member]
USD ($)
Dec. 31, 2014
Designated as Hedges [Member]
Net Investment Hedge [Member]
Foreign Exchange Forward Contracts [Member]
EUR (€)
Mar. 31, 2015
Not Designated as Hedges [Member]
Interest Rate Swaps [Member]
USD ($)
transactions
Dec. 31, 2014
Not Designated as Hedges [Member]
Interest Rate Swaps [Member]
USD ($)
Mar. 31, 2015
Not Designated as Hedges [Member]
Foreign Exchange Forward Contracts [Member]
USD ($)
transactions
Mar. 31, 2015
Not Designated as Hedges [Member]
Foreign Exchange Forward Contracts [Member]
EUR (€)
Mar. 31, 2015
Not Designated as Hedges [Member]
Foreign Exchange Forward Contracts [Member]
GBP (£)
Mar. 31, 2015
Not Designated as Hedges [Member]
Foreign Exchange Forward Contracts [Member]
SGD
Dec. 31, 2014
Not Designated as Hedges [Member]
Foreign Exchange Forward Contracts [Member]
USD ($)
Dec. 31, 2014
Not Designated as Hedges [Member]
Foreign Exchange Forward Contracts [Member]
CHF
Dec. 31, 2014
Not Designated as Hedges [Member]
Foreign Exchange Forward Contracts [Member]
EUR (€)
Dec. 31, 2014
Not Designated as Hedges [Member]
Foreign Exchange Forward Contracts [Member]
GBP (£)
Dec. 31, 2014
Not Designated as Hedges [Member]
Foreign Exchange Forward Contracts [Member]
SGD
Mar. 31, 2015
Not Designated as Hedges [Member]
Forward Delivery Contracts [Member]
USD ($)
transactions
Dec. 31, 2014
Not Designated as Hedges [Member]
Forward Delivery Contracts [Member]
USD ($)
Mar. 31, 2015
Not Designated as Hedges [Member]
Interest Rate Lock Commitments [Member]
USD ($)
transactions
Dec. 31, 2014
Not Designated as Hedges [Member]
Interest Rate Lock Commitments [Member]
USD ($)
Mar. 31, 2015
Not Designated as Hedges [Member]
When-Issued Mortgage-Backed Securities [Member]
USD ($)
transactions
Dec. 31, 2014
Not Designated as Hedges [Member]
When-Issued Mortgage-Backed Securities [Member]
USD ($)
transactions
Derivatives, Fair Value [Line Items]                                                      
Derivative, notional amount     $ 4,100 $ 4,100 $ 4,237 $ 5,507 $ 2 [1] € 2 [1] $ 7 [1] € 6 [1] $ 277 [2] $ 359 [2] $ 36 [3] € 23 £ 6 1 $ 53 [3] 8 € 27 £ 8 1 $ 1,477 $ 761 $ 689 [2] $ 406 [2] $ 17 $ 33
Derivative, number of outstanding derivative contracts (in transactions)     8   162   1 1     1 [2]   7 7 7 7           416   2,785 [2]   1 1
Derivative assets 57 [4] 43 [4] 0 4 39 31 0   0   0 [2] 0 [2] 0       0         4 1 14 [2] 7 [2]    
Collateral held, derivative assets (26) [5] (20) [5]                                                  
Total net derivative assets 31 23                                                  
Derivative liabilities 55 [4] 23 [4] 50 18 0 2 0   0   0 [2] 0 [2] 0       0         5 3 0 [2] 0 [2]    
Collateral posted, derivative liabilities (51) [5] (23) [5]                                                  
Total net derivative liabilities $ 4 $ 0                                                  
[1] The foreign exchange forward contract has a notional amount of EUR 2 million and EUR 6 million as of March 31, 2015 and December 31, 2014, respectively.
[2] Interest rate swaps not designated as hedges and interest rate lock commitments do not have associated master netting arrangements.
[3] The foreign exchange forward contracts have notional amounts of EUR 23 million, GBP 6 million and SGD 1 million as of March 31, 2015 and EUR 27 million, GBP 8 million, SGD 1 million and CHF 8 million as of December 31, 2014.
[4] In addition to the derivatives disclosed in the table, the Company enters into forward contracts to purchase when-issued mortgage-backed securities as part of its community reinvestment initiatives. At March 31, 2015, the Company had one outstanding contract with a notional amount of $17 million and immaterial fair value. At December 31, 2014, the Company had one outstanding contract with a notional amount of $33 million and immaterial fair value.
[5] Collateral amounts, which consist of both cash and investment securities, are limited to the related derivative asset/liability balance and do not include excess collateral received/pledged.