Financial Instruments Temporarily Impaired Securities (Details) (Temporarily Impaired Securities [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Insurance Subsidiary Temporarily Impaired Investments [Line Items]
Available-for-sale Securities	$ 16	$ 17
Equity Securities [Member]
Insurance Subsidiary Temporarily Impaired Investments [Line Items]
Available-for-sale Securities	0	0
Number Of Securities	2	3
Fixed Maturities [Member]
Insurance Subsidiary Temporarily Impaired Investments [Line Items]
Available-for-sale Securities	16	17
Fixed Maturities [Member] | US Government and Government Agencies and Authorities [Member]
Insurance Subsidiary Temporarily Impaired Investments [Line Items]
Available-for-sale Securities	4	6
Number Of Securities	5	8
Fixed Maturities [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Insurance Subsidiary Temporarily Impaired Investments [Line Items]
Available-for-sale Securities	8	8
Number Of Securities	16	18
Fixed Maturities [Member] | Other Government Securities [Member]
Insurance Subsidiary Temporarily Impaired Investments [Line Items]
Available-for-sale Securities	3	1
Number Of Securities	7	3
Fixed Maturities [Member] | Corporate Bond Securities [Member]
Insurance Subsidiary Temporarily Impaired Investments [Line Items]
Available-for-sale Securities	1	2
Number Of Securities	3	3
Maximum [Member]
Insurance Subsidiary Temporarily Impaired Investments [Line Items]
Available-for-sale Securities, Gross Unrealized Losses	$ 1	$ 1
Expiring One Year From Balance Sheet Date [Member]
Insurance Subsidiary Temporarily Impaired Investments [Line Items]
Number Of Securities	14
Expiring After One Year From Balance Sheet Date [Member]
Insurance Subsidiary Temporarily Impaired Investments [Line Items]
Number Of Securities	17