Debt (Details) - USD ($) $ in Millions			3 Months Ended
	Apr. 15, 2016	Apr. 06, 2016	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
Lines of Credit [Abstract]
Available and unused credit lines			$ 3,669.7		$ 3,657.7
Short-Term Borrowings [Abstract]
Short-term debt			38.8		5.2
Long-Term Notes Payable [Abstract]
Long-term debt, carrying amount			4,500.3		4,500.3
Unamortized premium (discount) on senior notes, net			9.9		10.1
Debt issuance costs			(16.0)		(16.9)
Adjustment to carrying value for interest rate swaps			118.7		72.1
Long-term notes payable, total			4,612.9		4,565.6
Long-term notes payable, current portion			(1,000.2)		(1,001.4)
Long-Term Debt			3,612.7		3,564.2
Accumulated other comprehensive income (loss)			(949.3)	$ (936.7)	(1,015.4)	$ (618.2)
Interest rate swaps, gain on termination			$ 54.2	0.0
Current Fiscal Year End Date			--12-31
Subsequent Event [Member]
Long-Term Notes Payable [Abstract]
Long-term debt, carrying amount		$ 4,900.0
Unamortized Loss on Cash Flow Hedge
Long-Term Notes Payable [Abstract]
Accumulated other comprehensive income (loss)			$ (31.8)	$ (2.5)	(3.3)	$ 0.0
Cash Flow Hedge [Member]
Long-Term Notes Payable [Abstract]
Interest rate swaps, liability, at fair value			54.5
Accumulated other comprehensive income (loss)			(31.8)
Interest Rate Swap [Member] | Subsequent Event [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]
Interest rate swaps, notional amount					1,000.0
Interest rate swaps, gain on termination			54.2
Interest Rate Swaps on 2024 Notes [Member]
Long-Term Notes Payable [Abstract]
Interest rate swaps, asset, at fair value			20.2
Interest rate swaps, liability, at fair value					10.0
Interest rate swaps, notional amount			750.0
Interest Rate Swaps on 2026 Notes [Member] | Subsequent Event [Member]
Long-Term Notes Payable [Abstract]
Interest rate swaps, notional amount		$ 500.0
Interest Rate Swaps on 2026 Notes [Member] | LIBOR [Member] | Subsequent Event [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, 2020
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 March 31, 2016 we were in compliance with these covenants as our Leverage Ratio was 2.1 times and our Interest Coverage Ratio was 11.9 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			1,169.7		1,157.7
5.9% Senior Notes due 2016
Long-Term Notes Payable [Abstract]
Long-term debt, carrying amount			$ 1,000.0		1,000.0
Long-term debt, interest rate			5.90%
Long-term debt, maturity date			Apr. 15, 2016
5.9% Senior Notes due 2016 | Subsequent Event [Member]
Long-Term Notes Payable [Abstract]
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 | Subsequent Event [Member]
Long-Term Notes Payable [Abstract]
Long-term debt, carrying amount		$ 1,400.0
Long-term debt, interest rate		3.60%
Long-term debt, maturity date		Apr. 15, 2026
Long-term debt, proceeds from issuance		$ 1,387.0
Debt Instrument, Interest Rate, Effective Percentage		4.10%
Other debt
Long-Term Notes Payable [Abstract]
Long-term debt, carrying amount			$ 0.3		$ 0.3