Fair Value Measurements - Not Carried at Fair Value (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Commercial Mortgage Loans	$ 2,252	$ 2,851
Percentage of contractholder deposit funds that can be withdrawn at any time	60.00%
Estimate Of Fair Value Fair Value Disclosure [Member] | Fair Value Inputs Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, including current maturities, excluding capital leases	5,550	5,821
Estimate Of Fair Value Fair Value Disclosure [Member] | Fair Value Inputs Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Commercial Mortgage Loans	2,338	2,999
Contractholder deposit funds, excluding universal life products	1,081	1,082
Carrying Reported Amount Fair Value Disclosure [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Commercial Mortgage Loans	2,252	2,851
Contractholder deposit funds, excluding universal life products	1,072	1,056
Long-term debt, including current maturities, excluding capital leases	$ 4,997	$ 4,986