Commitments and Contingencies, Technology Agreements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
IBM Agreement [Member]
Technology Agreements [Abstract]
Technology Agreement Expiration Date	2019
Percent of contract value to be paid if contract is terminated (in hundredths)	50.00%
Amount capitalized or expensed under technology agreement	$ 118.7	$ 109.5	$ 111.3
Technology Agreements, Minimum Payments Due [Abstract]
2017	31.6
2018	30.6
2019	30.5
2020	0.0
2021	0.0
Thereafter	$ 0.0
Accenture Agreement [Member]
Technology Agreements [Abstract]
Technology Agreement Expiration Date	2020
Amount capitalized or expensed under technology agreement	$ 34.6	$ 17.3	$ 27.3
Technology Agreements, Minimum Payments Due [Abstract]
2017	10.0
2018	10.5
2019	10.7
2020	11.0
2021	0.0
Thereafter	$ 0.0