Separate Accounts, Death Benefits and Other Insurance Benefit Features and Embedded Product Derivatives Changes in Additional Liability Balances (Details) (Universal Life, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Universal Life
Net Amount at Risk by Product and Guarantee [Line Items]
Liability balance, beginning of the period	$ 300.4	$ 203.0	$ 109.7
Incurred	48.6	37.1	138.8
Change due to net unrealized gains or losses included in AOCI	0.6	(16.9)	(0.4)
Assumption unlocking	(75.0)	43.4	(45.9)
Liability balance, end of the period	$ 273.4	$ 300.4	$ 203.0