XML 75 R58.htm IDEA: XBRL DOCUMENT v3.7.0.1
Fair value measurements Insurance contracts (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2016
Fair Value Disclosures [Abstract]          
Investments used to satisfy nonqualified benefit plans obligations $ 73.1 $ 71.4 $ 73.1 $ 71.4 $ 70.9
Net unrealized gain (loss) of investments used to satisfy obligations under nonqualified benefit plans $ 2.1 $ 2.3 $ 5.0 $ 3.9