AMPS Exchange Total Surplus Notes Issued

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- Definition

Junior Surplus Notes issued by the Segregated Account of Ambac Assurance to Ambac upon Ambac's emergence from bankruptcy. These Junior Surplus notes will be includable in surplus for statutory accounting purposes as prescribed or permitted by state laws and regulations.

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Debt Instrument Principal Amount Subject To Reduction

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- Definition

Interest Rate on Ambac Note Post Exit From Rehabilitation

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- Definition

Long-term Debt Issued in Exchange Transaction

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- Definition

One Time Interest Payment on Surplus Notes

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- Definition

Paydown of Ambac Note

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Tier 2 Note Security in RMBS Litigation Settlement Proceeds

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Unpaid Principal Amount Of Fixed Rate Debt Accounted For Under Fair Value Option

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Face (par) amount of debt instrument at time of issuance.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount of unamortized debt discount (premium) and debt issuance costs.

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Gross amount of debt extinguished.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Interest paid other than in cash for example by issuing additional debt securities. As a noncash item, it is added to net income when calculating cash provided by or used in operations using the indirect method.

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Long-Term Debt (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Long-Term Debt (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 19, 2021	Aug. 03, 2018	Feb. 12, 2018	May 01, 2013
Debt Instrument [Line Items]
Tier 2 Note Security in RMBS Litigation Settlement Proceeds							$ 1,600
Long-term debt		$ 2,739	$ 2,822
One Time Interest Payment on Surplus Notes							14
Junior surplus note of Ambac Assurance Segregated Account								$ 350
AMPS Exchange Total Surplus Notes Issued						$ 213
Net realized gains (losses) on extinguishment of debt		0	0	$ 3
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months		531
Long-term Debt, Maturities, Repayments of Principal in Year Two		0
Long-term Debt, Maturities, Repayments of Principal in Year Three		1,641
Long-term Debt, Maturities, Repayments of Principal in Year Four		0
Long-term Debt, Maturities, Repayments of Principal in Year Five		0
Paydown of Ambac Note		121	178	$ 214
Long-term Debt, Maturities, Repayments of Principal after Year Five		$ 712
Ambac Note Post Exit From Rehabilitation [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		7.60%
Paydown of Ambac Note		$ (121)	(178)
Tier 2 Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		8.50%
Debt Instrument, Interest Rate, Effective Percentage		9.90%
Debt Instrument, Face Amount		$ 306
Paid-in-Kind Interest		$ 66	41
5.1% Surplus Notes, General Account, Due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		10.10%
5.1% Junior Surplus Notes, Segregated Account Due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		19.50%
One State Street [Member] \| 5.1% Junior Surplus Notes, Segregated Account Due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 15	15
Debt Instrument Principal Amount Subject To Repurchase		0
Extinguishment of Debt, Amount	$ 2	$ 0
Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member] \| 5.1% Junior Surplus Notes, Segregated Account Due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		8.40%
Ambac Assurance Corporation [Member]
Debt Instrument [Line Items]
Long-term debt		$ 2,739	2,822
Long-term Debt, Gross		2,884	2,980
Debt Instrument, Unamortized Discount (Premium), Net		(145)	(159)
Ambac Assurance Corporation [Member] \| 5.1% Junior Surplus Notes, General Account Due 2020 [Member]
Debt Instrument [Line Items]
Long-term debt		247	252
Long-term Debt, Gross		365	365
Debt Instrument, Unamortized Discount (Premium), Net		(118)	(113)
Ambac Assurance Corporation [Member] \| Ambac Note Post Exit From Rehabilitation [Member]
Debt Instrument [Line Items]
Long-term debt		1,641	1,763
Long-term Debt, Gross		1,641	1,763
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Ambac Assurance Corporation [Member] \| Tier 2 Notes [Member]
Debt Instrument [Line Items]
Long-term debt		306	278
Long-term Debt, Gross		306	281
Debt Instrument, Unamortized Discount (Premium), Net		0	(4)
Ambac Assurance Corporation [Member] \| 5.1% Surplus Notes, General Account, Due 2020 [Member]
Debt Instrument [Line Items]
Long-term debt		531	517
Long-term Debt, Gross		531	531
Debt Instrument, Unamortized Discount (Premium), Net		$ 0	(14)
Ambac Assurance Corporation [Member] \| 5.1% Surplus Notes, General Account, Due 2020 [Member] \| Corolla Notes
Debt Instrument [Line Items]
Long-term Debt Issued in Exchange Transaction					$ 267
Ambac Assurance Corporation [Member] \| 5.1% Surplus Notes, General Account, Due 2020 [Member] \| Corolla Notes and Lease Reducing
Debt Instrument [Line Items]
Long-term Debt Issued in Exchange Transaction					$ 279
Ambac UK [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		0.00%
Long-term debt		$ 14	13
Long-term Debt, Gross		41	41
Debt Instrument, Unamortized Discount (Premium), Net		$ (27)	$ (28)
Debt Instrument, Interest Rate, Effective Percentage		7.40%
5.1% Junior Surplus Notes Due 2020 [Member] \| Ambac Assurance Corporation [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.10%	5.10%
5.1 % Surplus Notes Due 2020 [Member] \| Ambac Assurance Corporation [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.10%	5.10%
5.1 % Surplus Notes Due 2020 [Member] \| Ambac Assurance Corporation [Member] \| Corolla Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					5.10%
Consolidated Variable Interest Entities [Member]
Debt Instrument [Line Items]
Unpaid Principal Amount Of Fixed Rate Debt Accounted For Under Fair Value Option		$ 3,927	$ 3,990
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months		0
Long-term Debt, Maturities, Repayments of Principal in Year Two		0
Long-term Debt, Maturities, Repayments of Principal in Year Three		0
Long-term Debt, Maturities, Repayments of Principal in Year Four		0
Long-term Debt, Maturities, Repayments of Principal in Year Five		83
Long-term Debt, Maturities, Repayments of Principal after Year Five		$ 3,844
Consolidated Variable Interest Entities [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		0.00%	0.00%
Consolidated Variable Interest Entities [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		7.93%	7.93%
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate on Ambac Note Post Exit From Rehabilitation		5.00%
London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Interest Rate on Ambac Note Post Exit From Rehabilitation		1.00%
Ambac [Member]
Debt Instrument [Line Items]
One Time Interest Payment on Surplus Notes							$ 3
Long-term Debt [Member]
Debt Instrument [Line Items]
Gain Contingency, Unrecorded Amount		$ 1,400