Debt (Details) - USD ($) $ in Millions		1 Months Ended	9 Months Ended
	Apr. 05, 2017	Sep. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Long-Term Debt
Less deferred debt issuance costs		$ (14.0)	$ (14.0)	$ (12.3)
Total debt		3,560.8	3,560.8	3,010.7
Less current portion		1.1	1.1	375.2
Total long-term debt		3,559.7	3,559.7	2,635.5
Total debt, Approximate Fair Value		3,623.5	3,623.5	3,062.2
Less short-term debt, Approximate Fair Value		1.1	1.1	375.7
Long-term debt, Approximate Fair Value		3,622.4	3,622.4	2,686.5
The “Revolving Credit Facility”
Long-Term Debt
Maximum borrowing capacity		2,000.0	2,000.0
Borrowings under the Revolving Credit Facility		0.0	0.0
Commercial Paper Program
Long-Term Debt
Debt carrying amount, net of unamortized discount before deferred debt issuance costs		1,191.9	1,191.9	1,018.9
Total debt, Approximate Fair Value		1,191.9	1,191.9	$ 1,018.9
Maximum borrowing capacity		$ 2,000.0	$ 2,000.0
Maximum maturity term			397 days
Average interest rate (as a percent)		1.48%	1.48%
Senior Notes
Long-Term Debt
Redemption price as a percentage of principal amount			100.00%
1.55% Senior Notes due September 2017
Long-Term Debt
Stated interest rate (as a percent)		1.55%	1.55%	1.55%
Debt carrying amount, net of unamortized discount before deferred debt issuance costs				$ 374.9
Total debt, Approximate Fair Value				$ 375.4
Repayment of debt		$ 375.0
2.55% Senior Notes due January 2019
Long-Term Debt
Stated interest rate (as a percent)		2.55%	2.55%	2.55%
Debt carrying amount, net of unamortized discount before deferred debt issuance costs		$ 749.7	$ 749.7	$ 749.5
Total debt, Approximate Fair Value		$ 756.1	$ 756.1	$ 758.3
2.20% Senior Notes due April 2020
Long-Term Debt
Stated interest rate (as a percent)	2.20%	2.20%	2.20%
Debt carrying amount, net of unamortized discount before deferred debt issuance costs		$ 399.7	$ 399.7
Total debt, Approximate Fair Value		$ 400.6	$ 400.6
Debt instrument, principal amount	$ 400.0
Debt instrument, face amount, net of discount (as a percent)	99.922%
Redemption price as a percentage of principal amount	100.00%
3.125% Senior Notes due September 2021
Long-Term Debt
Stated interest rate (as a percent)		3.125%	3.125%	3.125%
Debt carrying amount, net of unamortized discount before deferred debt issuance costs		$ 374.8	$ 374.8	$ 374.8
Total debt, Approximate Fair Value		$ 383.5	$ 383.5	$ 380.4
4.00% Senior Notes due February 2022
Long-Term Debt
Stated interest rate (as a percent)		4.00%	4.00%	4.00%
Debt carrying amount, net of unamortized discount before deferred debt issuance costs		$ 499.5	$ 499.5	$ 499.4
Total debt, Approximate Fair Value		$ 527.7	$ 527.7	523.7
3.20% Senior Notes due April 2024
Long-Term Debt
Stated interest rate (as a percent)	3.20%	3.20%	3.20%
Debt carrying amount, net of unamortized discount before deferred debt issuance costs		$ 349.6	$ 349.6
Total debt, Approximate Fair Value		354.1	354.1
Debt instrument, principal amount	$ 350.0
Debt instrument, face amount, net of discount (as a percent)	99.888%
Redemption price as a percentage of principal amount	100.00%
Notes payable to foreign banks and other debt
Long-Term Debt
Debt carrying amount, net of unamortized discount before deferred debt issuance costs		9.6	9.6	5.5
Total debt, Approximate Fair Value		9.6	9.6	$ 5.5
2.20% and 3.20% Senior Notes due April, 2020 and 2024, respectively
Long-Term Debt
Debt issuance costs incurred		$ 5.2	$ 5.2