Consolidated Statements Of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Consolidated Statements Of Comprehensive Income [Abstract]
Net income	$ 49.8	$ 60.6
Other comprehensive income, net of tax:
Unrealized loss on securities, net of tax of $0.1 for 2013	0.1	0.1
Other comprehensive income	0.1	0.1
Comprehensive income	$ 49.9	$ 60.7