Fair Value of Assets and Liabilities (Details 5) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
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	$ (2)	$ 29
Gains (losses) for Level 3 liabilities still held at the balance sheet date, included in earnings	6	(25)
Gains (losses) for Level 3 assets and liabilities still held at the balance sheet date, included in earnings	4	4
Gains (losses) for Level 3 assets still held at the balance sheet date, included in realized capital gains and losses	(8)	24
Gains (losses) for Level 3 assets still held at the balance sheet date, included in investment income	6	5
Losses (gains) for Level 3 assets still held at the balance sheet date, included in interest credited to contract holder funds	(20)	(56)
Losses (gains) for Level 3 liabilities still held at the balance sheet date, included in life and annuity contract benefits	26	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	6	(25)
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	(10)	14
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	(14)	(1)
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	5	3
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		13
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	(1)	(1)
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	1
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	$ 7	$ 15