Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Schedule of Net Deferred Acquisition Costs

The following table sets forth net deferred acquisition costs for the years ended December 31, 2018, 2017 and 2016:

($ millions)	2018		2017		2016
Balance, beginning of year	$	110.3	$	121.8	$	120.4
Acquisition costs deferred	211.5		230.8		269.3
Acquisition costs amortized to expense	(220.0)		(242.3)		(267.9)
Balance, end of year	$	101.9	$	110.3	$	121.8