Investments (Fixed Maturity and Equity Securities Available-For-Sale - Narrative) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Summary of Certain Fixed Maturity Securities
Gross Unrealized OTTI Loss	$ 180	$ 218	$ 361
Available-for-sale Securities, Debt Securities	355,069	350,187
Foreign corporate securities [Member]
Summary of Certain Fixed Maturity Securities
Gross Unrealized OTTI Loss	0	0
Available-for-sale Securities, Debt Securities	64,177	63,152
Gross Unrealized Gain	4,543	3,939
Non-income producing fixed maturity securities [Member]
Summary of Certain Fixed Maturity Securities
Available-for-sale Securities, Debt Securities	49	74
Gross Unrealized Gain	$ 26	$ 23