Investments (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2011	Dec. 31, 2010	Dec. 31, 2009
Fixed Maturity and Equity Securities Available-for-Sale
Amortized Cost	$ 330,903	$ 317,617
Gross Unrealized Temporary Loss	(115)	(241)
Gross Unrealized OTTI Loss	739	601	859
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $330,903 and $317,617, respectively; includes $3,357 and $3,330, respectively, relating to variable interest entities)	341,744	324,797
Equity securities	3,238	3,602
Foreign corporate securities [Member]
Fixed Maturity and Equity Securities Available-for-Sale
Amortized Cost	67,518	65,487
Gross Unrealized Gain	3,877	3,326
Gross Unrealized Temporary Loss	858	925
Gross Unrealized OTTI Loss	(1)	0
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $330,903 and $317,617, respectively; includes $3,357 and $3,330, respectively, relating to variable interest entities)	70,538	67,888
% of Total	20.60%	20.90%
Foreign government debt securities [Member]
Fixed Maturity and Equity Securities Available-for-Sale
Amortized Cost	47,750	40,871
Gross Unrealized Gain	2,046	1,733
Gross Unrealized Temporary Loss	389	602
Gross Unrealized OTTI Loss	161	0
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $330,903 and $317,617, respectively; includes $3,357 and $3,330, respectively, relating to variable interest entities)	49,246	42,002
% of Total	14.40%	12.90%
Non-redeemable preferred stock [Member]
Fixed Maturity and Equity Securities Available-for-Sale
Cost or Amortized Cost	1,169	1,562
Gross Unrealized Gain	83	76
Gross Unrealized Temporary Loss	104	229
Gross Unrealized OTTI Loss	0	0
Equity securities	1,148	1,409
% of Total	35.50%	39.10%
Fixed maturity securities [Member]
Fixed Maturity and Equity Securities Available-for-Sale
Amortized Cost	330,903	317,617
Gross Unrealized Gain	16,178	13,760
Gross Unrealized Temporary Loss	4,598	5,979
Gross Unrealized OTTI Loss	739	601
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $330,903 and $317,617, respectively; includes $3,357 and $3,330, respectively, relating to variable interest entities)	341,744	324,797
% of Total	100.00%	100.00%
U.S. corporate securities [Member]
Fixed Maturity and Equity Securities Available-for-Sale
Amortized Cost	92,677	88,905
Gross Unrealized Gain	5,244	4,469
Gross Unrealized Temporary Loss	1,124	1,602
Gross Unrealized OTTI Loss	0	0
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $330,903 and $317,617, respectively; includes $3,357 and $3,330, respectively, relating to variable interest entities)	96,797	91,772
% of Total	28.30%	28.30%
RMBS [Member]
Fixed Maturity and Equity Securities Available-for-Sale
Amortized Cost	42,845	44,468
Gross Unrealized Gain	1,870	1,652
Gross Unrealized Temporary Loss	652	917
Gross Unrealized OTTI Loss	513	470
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $330,903 and $317,617, respectively; includes $3,357 and $3,330, respectively, relating to variable interest entities)	43,550	44,733
% of Total	12.80%	13.80%
U.S. Treasury and agency securities [Member]
Fixed Maturity and Equity Securities Available-for-Sale
Amortized Cost	34,691	32,469
Gross Unrealized Gain	1,462	1,394
Gross Unrealized Temporary Loss	588	559
Gross Unrealized OTTI Loss	0	0
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $330,903 and $317,617, respectively; includes $3,357 and $3,330, respectively, relating to variable interest entities)	35,565	33,304
% of Total	10.40%	10.20%
CMBS [Member]
Fixed Maturity and Equity Securities Available-for-Sale
Amortized Cost	18,782	20,213
Gross Unrealized Gain	906	740
Gross Unrealized Temporary Loss	176	266
Gross Unrealized OTTI Loss	(6)	12
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $330,903 and $317,617, respectively; includes $3,357 and $3,330, respectively, relating to variable interest entities)	19,518	20,675
% of Total	5.70%	6.40%
ABS [Member]
Fixed Maturity and Equity Securities Available-for-Sale
Amortized Cost	15,082	14,722
Gross Unrealized Gain	330	274
Gross Unrealized Temporary Loss	483	590
Gross Unrealized OTTI Loss	72	119
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $330,903 and $317,617, respectively; includes $3,357 and $3,330, respectively, relating to variable interest entities)	14,857	14,287
% of Total	4.40%	4.40%
State and political subdivision securities [Member]
Fixed Maturity and Equity Securities Available-for-Sale
Amortized Cost	11,554	10,476
Gross Unrealized Gain	443	171
Gross Unrealized Temporary Loss	328	518
Gross Unrealized OTTI Loss	0	0
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $330,903 and $317,617, respectively; includes $3,357 and $3,330, respectively, relating to variable interest entities)	11,669	10,129
% of Total	3.40%	3.10%
Other fixed maturity securities [Member]
Fixed Maturity and Equity Securities Available-for-Sale
Amortized Cost	4	6
Gross Unrealized Gain	0	1
Gross Unrealized Temporary Loss	0	0
Gross Unrealized OTTI Loss	0	0
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $330,903 and $317,617, respectively; includes $3,357 and $3,330, respectively, relating to variable interest entities)	4	7
% of Total	0.00%	0.00%
Equity Securities [Member]
Fixed Maturity and Equity Securities Available-for-Sale
Cost or Amortized Cost	3,128	3,621
Gross Unrealized Gain	225	222
Gross Unrealized Temporary Loss	115	241
Gross Unrealized OTTI Loss	0	0
Equity securities	3,238	3,602
% of Total	100.00%	100.00%
Common stock [Member]
Fixed Maturity and Equity Securities Available-for-Sale
Cost or Amortized Cost	1,959	2,059
Gross Unrealized Gain	142	146
Gross Unrealized Temporary Loss	11	12
Gross Unrealized OTTI Loss	0	0
Equity securities	$ 2,090	$ 2,193
% of Total	64.50%	60.90%

Equity securities available-for-sale, at cost.

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- Definition

This item represents the gross unrealized gains for securities which are categorized neither as held-to-maturity nor trading securities. Such gross unrealized gains are the excess of the fair value of the Available-for-sale Securities over their carrying value as of the reporting date. Such gross unrealized gains are included in other comprehensive income in the statement of shareholders' equity, unless the Available-for-sale Security is designated as a hedge. All or a portion of the unrealized holding gain of an available-for-sale security that is designated as being hedged in a fair value hedge shall be recognized in earnings during the period of the hedge.

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- Definition

Equity securities available-for-sale, at estimated fair value.

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- Definition

This item represents the gross unrealized losses for securities which are categorized neither as held-to-maturity nor trading securities. Such gross unrealized losses are the excess of the carrying value of the Available-for-sale Securities over their fair value as of the reporting date. Such gross unrealized losses are included in other comprehensive income in the statement of shareholders' equity, unless the Available-for-sale Security is designated as a hedge or is determined to have had an other than temporary decline in fair value below its amortized cost basis. All or a portion of the unrealized holding loss of an Available-for-sale Security that is designated as being hedged in a fair value hedge shall be recognized in earnings during the period of the hedge, as should other than temporary declines in fair value below costs basis.

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- Definition

This item represents the gross unrealized losses for equity securities. Such gross unrealized losses are the excess of the carrying value of the Available-for-sale Securities over their fair value as of the reporting date. Such gross unrealized losses are included in other comprehensive income in the statement of shareholders' equity, unless the Available-for-sale Security is determined to have had an other than temporary decline in fair value below its cost basis. All or a portion of the unrealized holding loss of an Available-for-sale Security that is determined to have had an other than temporary decline in fair value below its cost basis shall be recognized in earnings during the period of decline.

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- Definition

Other-than-temporary impairments on fixed maturity securities transferred to other comprehensive income loss.

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- Definition

Other-than-temporary impairments on equity securities transferred to other comprehensive loss.

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- Definition

This element presents the estimated fair value of certain fixed maturity securities as a percentage of total estimated fair value of certain fixed maturity securities.

+ Details

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- Definition

This element presents the estimated fair value of certain equity securities as a percentage of total estimated fair value of certain equity securities.

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- Definition

This item represents the total of all debt securities grouped by maturity dates, at cost, net of adjustments made for accretion, amortization, other-than-temporary impairments, and hedging, if any, which are classified neither as held-to-maturity nor trading securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 7
-Footnote 2

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 20

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- Definition

For an unclassified balance sheet, total of debt securities categorized neither as held-to-maturity nor trading. Such securities are reported at fair value; unrealized gains and losses of such securities are excluded from earnings and included in other comprehensive income, a separate component of shareholders' equity, unless the Available-for-sale Security is designated as a hedge or is determined to have had an other than temporary decline in fair value below its amortized cost basis. All or a portion of the unrealized holding gain or loss of an Available-for-sale Security that is designated as being hedged in a fair value hedge shall be recognized in earnings during the period of the hedge, as should other than temporary declines in fair value below costs basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 13, 137

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 12
-Subparagraph b

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 16

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 22

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- Definition

For an unclassified balance sheet, this item represents equity securities categorized neither as held-to-maturity nor trading. Equity securities represent ownership interests or the right to acquire ownership interests in corporations and other legal entities which ownership interest is represented by shares of common or preferred stock (which is not mandatorily redeemable or redeemable at the option of the holder), convertible securities, stock rights, or stock warrants. Unrealized gains and losses related to Available-for-sale Securities are excluded from earnings and reported in a separate component of shareholders' equity (other comprehensive income), unless the Available-for-sale Security is designated as a hedge or is determined to have had an other than temporary decline in fair value below its amortized cost basis. All or a portion of the unrealized holding gain or loss of an Available-for-sale Security that is designated as being hedged in a fair value hedge shall be recognized in earnings during the period of the hedge, as should other than temporary declines in fair value below costs basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 22

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 19

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 12
-Subparagraph b

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 86-40

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 13

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 16

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 3
-Subparagraph c

+ Details

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