Schedule IV - Reinsurance (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount	$ 20,373	$ 18,075	$ 16,631
Ceded to Other Companies	27	21	17
Assumed from Other companies	16	19	7
Net Amount	20,362	18,073	16,621
Percentage of Amount Assumed to Net	0.00%	0.00%	0.00%
Life insurance in force
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount	168,355	149,045	128,649
Ceded to Other Companies	4,159	4,000	3,594
Assumed from Other companies	3	2	5
Net Amount	164,199	145,047	125,060
Percentage of Amount Assumed to Net	0.00%	0.00%	0.00%
Health insurance
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount	17,210	15,784	14,759
Ceded to Other Companies	14	9	4
Assumed from Other companies	12	18	6
Net Amount	17,208	15,793	14,761
Percentage of Amount Assumed to Net	0.00%	0.00%	0.00%
Life insurance
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount	3,163	2,291	1,872
Ceded to Other Companies	13	12	13
Assumed from Other companies	4	1	1
Net Amount	$ 3,154	$ 2,280	$ 1,860
Percentage of Amount Assumed to Net	0.00%	0.00%	0.00%

Amount of premiums assumed from other companies.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 17

-Article 12

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 235

-Section S99

-Paragraph 2

-Subparagraph (SX 210.12-17)

-URI http://asc.fasb.org/extlink&oid=6588446&loc=d3e574992-122915

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