Slicers (applies to each fact value in each table cell)

Reporting Entity [Axis]

0001156375 (http://www.sec.gov/CIK)

Debt Disclosure [Abstract]	Period [Axis]
	2016-01-01 - 2016-12-31
Debt Disclosure [Abstract]
Schedule of Long-term Debt	Long-term debt consisted of the following at December 31: (in millions)   2016   2015 $750.0 million fixed rate notes due September 2022, stated rate of 3.00% (1)   $ 745.2   $ 744.4 $750.0 million fixed rate notes due March 2025, stated rate of 3.00% (2)   744.2   743.4 $750.0 million fixed rate notes due September 2043, stated rate of 5.30% (3)   741.8   741.5 Total long-term debt   $ 2,231.2   $ 2,229.3  _______________ (1) In August 2012, the company entered into a forward-starting interest rate swap agreement that modified the interest obligation associated with these notes so that the interest payable on the notes effectively became fixed at a rate of 3.32%. (2) In December 2014, the company entered into a forward-starting interest rate swap agreement that modified the interest obligation associated with these notes so that the interest payable on the notes effectively became fixed at a rate of 3.11%. (3) In August 2012, the company entered into a forward-starting interest rate swap agreement that modified the interest obligation associated with these notes so that the interest payable on the notes effectively became fixed at a rate of 4.73%
Long-term debt maturities at par value	Long-term debt maturities, at par value, were as follows as of December 31, 2016: (in millions) Par Value 2017 $ — 2018 — 2019 — 2020 — 2021 — Thereafter 2,250.0