Debt (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013
Credit Lines [Abstract]
Available and unused credit lines	$ 3,767.7	$ 3,437.8
Short-Term Borrowings [Abstract]
Short-term borrowings	9.7	7.2
Long-Term Notes Payable [Abstract]
Long-term notes payable, carrying amount	4,500.4	4,500.5
Unamortized premium (discount) on Senior Notes, net	10.4	11.1
Adjustment to carrying value for interest rate swaps	94.8	51.4
Long-term notes payable, total	4,605.6	4,563.0
Long-term notes payable, current portion	(1,003.4)	(0.4)
Long-Term Notes Payable	3,602.2	4,562.6
Cash flow hedge liability, fair value	15.8
Cash flow hedge, accumulated gain, net of tax	(981.6)	(618.2)	$ (420.1)	$ (191.6)
Interest rate swaps, fair value	91.5	42.7
Credit Agreement
Credit Lines [Abstract]
Credit Agreement, maximum borrowing capacity	$ 2,500.0
Credit Agreement, expiration date	Jul. 31, 2020
Available and unused credit lines	$ 2,500.0	2,500.0
Credit Agreement, covenant terms	The Credit Agreement contains financial covenants that require us to maintain a Leverage Ratio of consolidated indebtedness to consolidated EBITDA of no more than 3 times for the most recently ended 12-month period (EBITDA is defined as earnings before interest, taxes, depreciation and amortization) and an Interest Coverage Ratio of consolidated EBITDA to interest expense of at least 5 times for the most recently ended 12-month period.
Credit Agreement, covenant compliance	At September 30, 2015 we were in compliance with these covenants as our Leverage Ratio was 2.1 times and our Interest Coverage Ratio was 12.6 times.
Credit Agreement | Commercial Paper [Member]
Credit Lines [Abstract]
Credit Agreement, maximum borrowing capacity	$ 2,000.0
Uncommitted credit lines
Credit Lines [Abstract]
Available and unused credit lines	1,267.7	937.8
5.9% Senior Notes due 2016
Long-Term Notes Payable [Abstract]
Long-term notes payable, carrying amount	$ 1,000.0	1,000.0
Interest rate	5.90%
Maturity date	Apr. 15, 2016
6.25% Senior Notes due 2019
Long-Term Notes Payable [Abstract]
Long-term notes payable, carrying amount	$ 500.0	500.0
Interest rate	6.25%
Maturity date	Jul. 15, 2019
4.45% Senior Notes due 2020
Long-Term Notes Payable [Abstract]
Long-term notes payable, carrying amount	$ 1,000.0	1,000.0
Interest rate	4.45%
Maturity date	Aug. 15, 2020
3.625% Senior Notes due 2022
Long-Term Notes Payable [Abstract]
Long-term notes payable, carrying amount	$ 1,250.0	1,250.0
Interest rate	3.625%
Maturity date	May 01, 2022
3.65% Senior Notes due 2024
Long-Term Notes Payable [Abstract]
Long-term notes payable, carrying amount	$ 750.0	750.0
Interest rate	3.65%
Maturity date	Nov. 01, 2024
Other notes and loans
Long-Term Notes Payable [Abstract]
Long-term notes payable, carrying amount	$ 0.4	0.5
Cash Flow Hedge [Member]
Long-Term Notes Payable [Abstract]
Cash flow hedge, notional amount	$ 1,000.0
Cash flow hedge, fixed interest rate	2.3209%
Cash flow hedge, inception date	Mar. 26, 2015
Cash flow hedge, maturity date	May 02, 2016
Interest Rate Swaps on 2022 Notes [Member]
Long-Term Notes Payable [Abstract]
Interest rate swaps, hedged amount	$ 1,250.0
Interest Rate Swaps on 2020 Notes [Member]
Long-Term Notes Payable [Abstract]
Interest rate swaps, hedged amount	1,000.0
Unrealized Gain (Loss) on Cash Flow Hedge
Long-Term Notes Payable [Abstract]
Cash flow hedge, accumulated gain, net of tax	$ (9.2)	$ 0.0	$ 0.0	$ 0.0
LIBOR [Member] | Interest Rate Swaps on 2022 Notes [Member]
Long-Term Notes Payable [Abstract]
Interest rate swaps, spread	1.05%
LIBOR [Member] | Interest Rate Swaps on 2020 Notes [Member]
Long-Term Notes Payable [Abstract]
Interest rate swaps, spread	2.16%