Commitments and Contingent Liabilities Commitments and Contingent Liabilities (Maximum Potential Obligation) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Commitment Period Two Thousand Twenty Six [Member]
Other Commitments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 500	$ 500
Commitment Period Two Thousand Thirty Three [Member]
Other Commitments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	1,850	1,350
Commitment Period Two Thousand Thirty Four [Member]
Other Commitments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	2,000	0
Commitment Period Two Thousand Thirty Six [Member]
Other Commitments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 1,250	$ 1,250