Fair value of financial instruments (Tables)

9 Months Ended

Sep. 30, 2015

Investments, Debt and Equity Securities [Abstract]

Schedule of Carrying Values and Estimated Fair Values of Debt Instruments

The fair value and carrying value of our fixed-rate debts are as follows:

(In millions)	September 30, 2015		December 31, 2014
Unsecured notes issued in a private placement
Carrying value	$	92.9	100.0
Fair value	96.0		105.6