Commitments Contingencies and Guarantees (Maximum Potential Obligation) (Details) $ in Millions	Dec. 31, 2016 USD ($)
Commitment Period Two Thousand Twenty Six [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 500.0
Commitment Period Two Thousand Thirty Three [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	950.0
Commitment Period Two Thousand Thirty Four [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	3,000.0
Commitment Period Two Thousand Thirty Five [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	1,314.2
Commitment Period Two Thousand Thirty Six [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 1,432.0