Fair Value Measurements (Summary of Assets and Liabilities at Fair Value) (Schedule) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Assets:
Derivative instruments:	$ 2,780.5	$ 2,496.7
Investments	1,070.0	1,174.8
Total assets	3,850.5	3,671.5
Liabilities:
Derivative instruments:	1,842.8	1,370.7
Debt	225.6	248.6
Total liabilities	2,068.4	1,619.3
Quoted prices in active markets for identical assets (Level 1)
Assets:
Derivative instruments:	0.0	0.0
Investments	624.1	755.9
Total assets	624.1	755.9
Liabilities:
Derivative instruments:	0.0	0.0
Debt	0.0	0.0
Total liabilities	0.0	0.0
Significant other observable inputs (Level 2)
Assets:
Derivative instruments:	1,924.5	1,750.1
Investments	0.0	0.0
Total assets	1,924.5	1,750.1
Liabilities:
Derivative instruments:	1,789.6	1,354.9
Debt	225.6	248.6
Total liabilities	2,015.2	1,603.5
Significant unobservable inputs (Level 3)
Assets:
Derivative instruments:	856.0	746.6
Investments	445.9	418.9
Total assets	1,301.9	1,165.5
Liabilities:
Derivative instruments:	53.2	15.8
Debt	0.0	0.0
Total liabilities	53.2	15.8
Cross-currency and interest rate derivative contracts
Assets:
Derivative instruments:	1,918.3	1,742.8
Liabilities:
Derivative instruments:	1,813.2	1,368.7
Cross-currency and interest rate derivative contracts | Quoted prices in active markets for identical assets (Level 1)
Assets:
Derivative instruments:	0.0	0.0
Liabilities:
Derivative instruments:	0.0	0.0
Cross-currency and interest rate derivative contracts | Significant other observable inputs (Level 2)
Assets:
Derivative instruments:	1,917.9	1,742.5
Liabilities:
Derivative instruments:	1,786.7	1,354.3
Cross-currency and interest rate derivative contracts | Significant unobservable inputs (Level 3)
Assets:
Derivative instruments:	0.4	0.3
Liabilities:
Derivative instruments:	26.5	14.4
Equity-related derivative instruments
Assets:
Derivative instruments:	855.6	746.3
Liabilities:
Derivative instruments:	1.0	1.4
Equity-related derivative instruments | Quoted prices in active markets for identical assets (Level 1)
Assets:
Derivative instruments:	0.0	0.0
Liabilities:
Derivative instruments:	0.0	0.0
Equity-related derivative instruments | Significant other observable inputs (Level 2)
Assets:
Derivative instruments:	0.0	0.0
Liabilities:
Derivative instruments:	0.0	0.0
Equity-related derivative instruments | Significant unobservable inputs (Level 3)
Assets:
Derivative instruments:	855.6	746.3
Liabilities:
Derivative instruments:	1.0	1.4
Foreign currency forward and option contracts
Assets:
Derivative instruments:	5.5	7.2
Liabilities:
Derivative instruments:	28.6	0.5
Foreign currency forward and option contracts | Quoted prices in active markets for identical assets (Level 1)
Assets:
Derivative instruments:	0.0	0.0
Liabilities:
Derivative instruments:	0.0	0.0
Foreign currency forward and option contracts | Significant other observable inputs (Level 2)
Assets:
Derivative instruments:	5.5	7.2
Liabilities:
Derivative instruments:	2.9	0.5
Foreign currency forward and option contracts | Significant unobservable inputs (Level 3)
Assets:
Derivative instruments:	0.0	0.0
Liabilities:
Derivative instruments:	25.7	0.0
Other
Assets:
Derivative instruments:	1.1	0.4
Liabilities:
Derivative instruments:	0.0	0.1
Other | Quoted prices in active markets for identical assets (Level 1)
Assets:
Derivative instruments:	0.0	0.0
Liabilities:
Derivative instruments:		0.0
Other | Significant other observable inputs (Level 2)
Assets:
Derivative instruments:	1.1	0.4
Liabilities:
Derivative instruments:		0.1
Other | Significant unobservable inputs (Level 3)
Assets:
Derivative instruments:	$ 0.0	0.0
Liabilities:
Derivative instruments:		$ 0.0