Contracts Accounted for as Insurance - Net Expected Loss to be Expensed Insurance Contracts (Details) $ in Millions	Mar. 31, 2019 USD ($)
Insurance [Abstract]
2019 (April 1 - June 30)	$ 9
2019 (July 1 - September 30)	9
2019 (October 1 - December 31)	8
Subtotal 2019	26
2020	35
2021	35
2022	36
2023	36
2024-2028	150
2029-2033	103
2034-2038	46
After 2038	10
Net expected loss to be expensed	477
Future accretion	15
Total expected future loss and LAE	$ 492

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

For financial guaranty insurance contracts, the amount of net loss expected to be expensed during the second quarter of the subsequent annual period following the statement of financial position reporting 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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No definition available.

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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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No definition available.

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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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- Definition

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

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No definition available.

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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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