Fair Value of Assets and Liabilities (Details 5) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Gains (losses) included in net income for Level 3 assets and liabilities:
Gains (losses) for Level 3 assets still held at the balance sheet date, included in earnings	$ (17)	$ (103)	$ (318)
Gains (losses) for Level 3 liabilities still held at the balance sheet date, included in earnings	168	(134)	(31)
Gains (losses) for Level 3 assets and liabilities still held at the balance sheet date, included in earnings	151	(237)	(349)
Gains (losses) for Level 3 assets still held at the balance sheet date, included in realized capital gains and losses	(37)	(147)	(402)
Gains (losses) for Level 3 assets still held at the balance sheet date, included in investment income	21	44	86
Losses (gains) for Level 3 assets still held at the balance sheet date, included in interest credited to contract holder funds	131	(102)	(2)
Losses (gains) for Level 3 liabilities still held at the balance sheet date, included in life and annuity contract benefits	36	(32)	(31)
Derivatives embedded in life and annuity contracts
Gains (losses) included in net income for Level 3 assets and liabilities:
Gains (losses) for Level 3 liabilities still held at the balance sheet date, included in earnings	168	(134)	(31)
Fixed income securities
Gains (losses) included in net income for Level 3 assets and liabilities:
Gains (losses) for Level 3 assets still held at the balance sheet date, included in earnings	(17)	(52)	(253)
Municipal
Gains (losses) included in net income for Level 3 assets and liabilities:
Gains (losses) for Level 3 assets still held at the balance sheet date, included in earnings	(28)	(28)	(33)
Corporate
Gains (losses) included in net income for Level 3 assets and liabilities:
Gains (losses) for Level 3 assets still held at the balance sheet date, included in earnings	15	20	40
Asset-backed securities ("ABS")
Gains (losses) included in net income for Level 3 assets and liabilities:
Gains (losses) for Level 3 assets still held at the balance sheet date, included in earnings		(33)	60
Residential mortgage-backed securities ("RMBS")
Gains (losses) included in net income for Level 3 assets and liabilities:
Gains (losses) for Level 3 assets still held at the balance sheet date, included in earnings	(1)		(292)
Commercial mortgage-backed securities ("CMBS")
Gains (losses) included in net income for Level 3 assets and liabilities:
Gains (losses) for Level 3 assets still held at the balance sheet date, included in earnings	(3)	(11)	(28)
Equity securities
Gains (losses) included in net income for Level 3 assets and liabilities:
Gains (losses) for Level 3 assets still held at the balance sheet date, included in earnings	(6)	(10)	(3)
Free-standing derivatives, net
Gains (losses) included in net income for Level 3 assets and liabilities:
Gains (losses) for Level 3 assets still held at the balance sheet date, included in earnings	6	(41)	(61)
Other assets
Gains (losses) included in net income for Level 3 assets and liabilities:
Gains (losses) for Level 3 assets still held at the balance sheet date, included in earnings			$ (1)