Contracts Accounted for as Insurance - Net Expected Loss to be Expensed Insurance Contracts (Details) $ in Millions	Jun. 30, 2018 USD ($)
Insurance [Abstract]
2018 (July 1 – September 30)	$ 9
2018 (October 1 – December 31)	9
Subtotal 2018	18
2019	40
2020	43
2021	44
2022	41
2023-2027	169
2028-2032	111
2033-2037	61
After 2037	13
Net expected loss to be expensed	540
Future accretion	170
Total expected future loss and LAE	$ 710

Financial Guarantee Insurance Contracts Future Expected Net Loss to be Expensed Beyond Twentieth Fiscal Year

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- Definition

Financial Guarantee Insurance Contracts Future Expected Net Loss to be Expensed During Fiscal Year Following Balance Sheet Date

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- Definition

Financial Guarantee Insurance Contracts Future Expected Net Loss to be Expensed During Fourth Quarter Following Balance Sheet Date

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- Definition

Financial Guarantee Insurance Contracts Future Expected Net Loss to be Expensed During Third Quarter Following Balance Sheet Date

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- Definition

Financial Guarantee Insurance Contracts Future Expected Net Loss to be Expensed More than 10 and within 15 Years from Balance Sheet Date

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- Definition

Financial Guarantee Insurance Contracts Future Expected Net Loss to be Expensed More than 15 and within 20 Years from Balance Sheet Date

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- Definition

For financial guarantee insurance contracts, the amount of net loss expected to be expensed during the sixth through tenth year following the statement of financial position reporting date.

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- Definition

Financial Guarantee Insurance Contracts Future Expected Net Loss to be Expensed in Fifth Full Fiscal Year

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- Definition

For financial guarantee insurance contracts, the amount of net loss expected to be expensed within the fourth full fiscal year following the date of the latest balance sheet presented in the financial statements.

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- Definition

For financial guaranty insurance contracts, the amount of net loss expected to be expensed within the second full fiscal year following the date of the latest balance sheet presented in the financial statements.

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Financial Guarantee Insurance Contracts, Future Expected, Net Loss to be Expensed in Third Full Fiscal Year

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- Definition

Financial Guarantee Insurance Contracts, Net Loss to be Expensed, Present Value

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- Definition

Financial Guarantee Insurance Contracts, Net Loss to be Expensed, Undiscounted

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- Definition

Schedule of Insured Financial Obligations with Credit Deterioration, Reductions of Gross Claim Liability, Net of Reinsurance Recoverable, Discount

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