Debt (Details) - USD ($) $ in Millions					9 Months Ended
	Apr. 15, 2016	Apr. 06, 2016	Mar. 28, 2016	Jan. 19, 2016	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Lines of Credit [Abstract]
Available and unused credit lines					$ 3,641.3		$ 3,657.7
Short-Term Borrowings [Abstract]
Short-term debt					25.0		5.2
Long-Term Notes Payable [Abstract]
Long-term debt, carrying amount					4,900.2		4,500.3
Unamortized premium (discount) on senior notes, net					8.0		10.1
Debt issuance costs					(25.2)		(16.9)
Adjustment to carrying value for interest rate swaps					124.5		72.1
Long-term notes payable, total					5,007.5		4,565.6
Long-term notes payable, current portion					(0.2)		(1,001.4)
Long-Term Debt					5,007.3		3,564.2
Long-term debt, proceeds from issuance					1,389.6	$ 0.0
Long-term debt, repayments					1,000.0	0.0
Deferred loss from settlement of forward-starting interest rate swap					54.5	0.0
Deferred gain from settlement of interest rate swap					$ 54.2	$ 0.0
Current Fiscal Year End Date					--12-31
Forward-Starting Interest Rate Swap [Member]
Long-Term Notes Payable [Abstract]
Deferred loss from settlement of forward-starting interest rate swap			$ 54.5
Interest Rate Swap [Member]
Long-Term Notes Payable [Abstract]
Interest rate swaps, notional amount					$ 1,250.0
Interest Rate Swaps on 2022 Notes [Member]
Long-Term Notes Payable [Abstract]
Deferred gain from settlement of interest rate swap				$ 54.2
Interest rate swaps, notional amount				$ 1,000.0
Interest Rate Swaps on 2024 Notes [Member]
Long-Term Notes Payable [Abstract]
Interest rate swaps, asset, at fair value					28.2
Interest rate swaps, liability, at fair value							10.0
Interest rate swaps, notional amount					750.0
Interest Rate Swaps on 2026 Notes [Member]
Long-Term Notes Payable [Abstract]
Interest rate swaps, asset, at fair value					6.9
Interest rate swaps, notional amount		$ 500.0
Interest Rate Swaps on 2026 Notes [Member] | LIBOR [Member]
Long-Term Notes Payable [Abstract]
Interest rate swaps, spread		1.982%
Credit Facility [Member]
Lines of Credit [Abstract]
Credit Agreement, maximum borrowing capacity					$ 2,500.0
Credit Agreement, expiration date					Jul. 31, 2021
Available and unused credit lines					$ 2,500.0		2,500.0
Credit Agreement, covenant terms					The Credit Facility 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, 2016 we were in compliance with these covenants as our Leverage Ratio was 2.2 times and our Interest Coverage Ratio was 11.1 times.
Commercial Paper [Member]
Lines of Credit [Abstract]
Credit Agreement, maximum borrowing capacity					$ 2,000.0
Uncommitted lines of credit [Member]
Lines of Credit [Abstract]
Available and unused credit lines					1,141.3		1,157.7
5.9% Senior Notes due 2016
Long-Term Notes Payable [Abstract]
Long-term debt, carrying amount					$ 0.0		1,000.0
Long-term debt, interest rate					5.90%
Long-term debt, maturity date					Apr. 15, 2016
Long-term debt, repayments	$ 1,000.0
6.25% Senior Notes due 2019
Long-Term Notes Payable [Abstract]
Long-term debt, carrying amount					$ 500.0		500.0
Long-term debt, interest rate					6.25%
Long-term debt, maturity date					Jul. 15, 2019
4.45% Senior Notes due 2020
Long-Term Notes Payable [Abstract]
Long-term debt, carrying amount					$ 1,000.0		1,000.0
Long-term debt, interest rate					4.45%
Long-term debt, maturity date					Aug. 15, 2020
3.625% Senior Notes due 2022
Long-Term Notes Payable [Abstract]
Long-term debt, carrying amount					$ 1,250.0		1,250.0
Long-term debt, interest rate					3.625%
Long-term debt, maturity date					May 01, 2022
3.65% Senior Notes due 2024
Long-Term Notes Payable [Abstract]
Long-term debt, carrying amount					$ 750.0		750.0
Long-term debt, interest rate					3.65%
Long-term debt, maturity date					Nov. 01, 2024
3.60% Senior Notes due 2026
Long-Term Notes Payable [Abstract]
Long-term debt, carrying amount		$ 1,400.0			$ 1,400.0		0.0
Long-term debt, interest rate		3.60%			3.60%
Long-term debt, maturity date		Apr. 15, 2026			Apr. 15, 2026
Long-term debt, proceeds from issuance		$ 1,387.0
Long-term debt, effective interest rate		4.10%
Other debt
Long-Term Notes Payable [Abstract]
Long-term debt, carrying amount					$ 0.2		$ 0.3