Fair Value Measurements (Carrying Amounts And Fair Values Of Financial Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Assets:
Available-for-sale securities	$ 170.1	$ 401.4
Carrying Amount
Assets:
Available-for-sale securities	170.1	401.4
Liabilities:
Short-term borrowings	2,594.8	845.2
Long-term borrowings	9,674.2	12,025.2
Fair Value
Assets:
Available-for-sale securities	170.1	401.4
Liabilities:
Short-term borrowings	2,594.8	845.2
Long-term borrowings	$ 10,095.1	$ 12,471.4