Investments (Details) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Available-for-sale securities
Amortized cost	$ 7,964	$ 7,643
Gross unrealized gains	552	533
Gross unrealized losses	55	39
Estimated fair value	8,461	8,137
Indemnity
Available-for-sale securities
Amortized cost	528	277
Gross unrealized gains	13	13
Gross unrealized losses	2	2
Estimated fair value	539	288
Indemnity \| Fixed maturities
Available-for-sale securities
Amortized cost	507	257
Gross unrealized gains	12	9
Gross unrealized losses	2	2
Estimated fair value	517	264
Indemnity \| U.S. government & agencies
Available-for-sale securities
Amortized cost		25
Gross unrealized gains		0
Gross unrealized losses		0
Estimated fair value		25
Indemnity \| States & political subdivisions
Available-for-sale securities
Amortized cost	213	193
Gross unrealized gains	11	6
Gross unrealized losses	0	2
Estimated fair value	224	197
Indemnity \| Corporate debt securities
Available-for-sale securities
Amortized cost	261	36
Gross unrealized gains	1	2
Gross unrealized losses	2	0
Estimated fair value	260	38
Indemnity \| Other debt securities
Available-for-sale securities
Amortized cost	9
Gross unrealized gains	0
Gross unrealized losses	0
Estimated fair value	9
Indemnity \| Commercial mortgage-backed securities (CMBS)
Available-for-sale securities
Amortized cost	20
Gross unrealized gains	0
Gross unrealized losses	0
Estimated fair value	20
Indemnity \| Collateralized debt obligations (CDO)
Available-for-sale securities
Amortized cost	4	3
Gross unrealized gains	0	1
Gross unrealized losses	0	0
Estimated fair value	4	4
Indemnity \| Nonredeemable preferred stock
Available-for-sale securities
Amortized cost	21	20
Gross unrealized gains	1	4
Gross unrealized losses	0	0
Estimated fair value	22	24
Exchange
Available-for-sale securities
Amortized cost	7,436	7,366
Gross unrealized gains	539	520
Gross unrealized losses	53	37
Estimated fair value	7,922	7,849
Exchange \| Fixed maturities
Available-for-sale securities
Amortized cost	6,877	6,863
Gross unrealized gains	493	446
Gross unrealized losses	39	30
Estimated fair value	7,331	7,279
Exchange \| U.S. government & agencies
Available-for-sale securities
Amortized cost	35	85
Gross unrealized gains	2	2
Gross unrealized losses	0	0
Estimated fair value	37	87
Exchange \| States & political subdivisions
Available-for-sale securities
Amortized cost	1,336	1,437
Gross unrealized gains	82	43
Gross unrealized losses	1	9
Estimated fair value	1,417	1,471
Exchange \| Foreign government securities
Available-for-sale securities
Amortized cost	20	20
Gross unrealized gains	1	1
Gross unrealized losses	0	0
Estimated fair value	21	21
Exchange \| Corporate debt securities
Available-for-sale securities
Amortized cost	5,094	4,900
Gross unrealized gains	385	377
Gross unrealized losses	33	14
Estimated fair value	5,446	5,263
Exchange \| Other debt securities
Available-for-sale securities
Amortized cost	66	54
Gross unrealized gains	2	3
Gross unrealized losses	0	0
Estimated fair value	68	57
Exchange \| Residential mortgage-backed securities (RMBS)
Available-for-sale securities
Amortized cost	191	216
Gross unrealized gains	12	9
Gross unrealized losses	0	1
Estimated fair value	203	224
Exchange \| Commercial mortgage-backed securities (CMBS)
Available-for-sale securities
Amortized cost	66	82
Gross unrealized gains	4	5
Gross unrealized losses	0	1
Estimated fair value	70	86
Exchange \| Collateralized debt obligations (CDO)
Available-for-sale securities
Amortized cost	69	69
Gross unrealized gains	5	6
Gross unrealized losses	5	5
Estimated fair value	69	70
Exchange \| Nonredeemable preferred stock
Available-for-sale securities
Amortized cost	559	503
Gross unrealized gains	46	74
Gross unrealized losses	14	7
Estimated fair value	$ 591	$ 570

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

+ References+ Details