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Segment Information - Reconciliation of Net Income (Loss) Attributable to AGL to Segment Adjusted Operating Income (Loss) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2022 | Jun. 30, 2021
Segment Reporting Information [Line Items] |  |  |  |
Revenues | $ 90 | $ 196 | $ 390 | $ 373
Expenses | 112 | 105 | 308 | 276
Equity in Earnings (Losses) of Investees | 0 | 34 | (11) | 43
Less: Provision (benefit) for income taxes | 3 | 23 | 21 | 23
Less: Noncontrolling interests | 22 | 4 | 31 | 8
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Realized gains (losses) on investments | (28) | 4 | (25) | 1
Fair value gains (losses) on committed capital securities | 10 | (6) | 11 | (25)
Total consolidated | (47) | 98 | 19 | 109
Revenues |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Total consolidated | 90 | 196 | 390 | 373
Expenses |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Total consolidated | 112 | 105 | 308 | 276
Equity in Earnings (Losses) of Investees |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Total consolidated | 0 | 34 | (11) | 43
Provision (Benefit) for Income Taxes |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Total consolidated | 3 | 23 | 21 | 23
Nonredeemable Noncontrolling Interests |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Total consolidated | 22 | 4 | 31 | 8
Net Income (Loss) Attributable to AGL |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Total consolidated | (47) | 98 | 19 | 109
Operating Segments |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 167 | 203 | 484 | 402
Expenses | 69 | 71 | 230 | 206
Equity in Earnings (Losses) of Investees | (34) | 48 | (35) | 67
Less: Provision (benefit) for income taxes | 9 | 30 | 31 | 41
Less: Noncontrolling interests | 0 | 0 | 0 | 0
Segment adjusted operating income (loss) | 55 | 150 | 188 | 222
Operating Segments | Insurance |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 139 | 182 | 417 | 361
Expenses | 41 | 47 | 163 | 153
Equity in Earnings (Losses) of Investees | (34) | 48 | (35) | 67
Less: Provision (benefit) for income taxes | 9 | 31 | 31 | 44
Less: Noncontrolling interests | 0 | 0 | 0 | 0
Segment adjusted operating income (loss) | 55 | 152 | 188 | 231
Operating Segments | Asset Management |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 28 | 21 | 67 | 41
Expenses | 28 | 24 | 67 | 53
Equity in Earnings (Losses) of Investees | 0 | 0 | 0 | 0
Less: Provision (benefit) for income taxes | 0 | (1) | 0 | (3)
Less: Noncontrolling interests | 0 | 0 | 0 | 0
Segment adjusted operating income (loss) | 0 | (2) | 0 | (9)
Corporate division |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 1 | 0 | 2 | 0
Expenses | 36 | 36 | 70 | 68
Equity in Earnings (Losses) of Investees | 0 | 0 | 0 | 0
Less: Provision (benefit) for income taxes | 0 | (2) | 0 | (5)
Less: Noncontrolling interests | 0 | 0 | 0 | 0
Segment adjusted operating income (loss) | (35) | (34) | (68) | (63)
Subtotal |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 175 | 230 | 507 | 450
Expenses | 112 | 111 | 312 | 285
Equity in Earnings (Losses) of Investees | 0 | 34 | (11) | 43
Less: Provision (benefit) for income taxes | 11 | 29 | 33 | 37
Less: Noncontrolling interests | 22 | 4 | 31 | 8
Segment adjusted operating income (loss) | 30 | 120 | 120 | 163
Other |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 7 | 27 | 21 | 48
Expenses | 7 | 4 | 12 | 11
Equity in Earnings (Losses) of Investees | 34 | (14) | 24 | (24)
Less: Provision (benefit) for income taxes | 2 | 1 | 2 | 1
Less: Noncontrolling interests | 22 | 4 | 31 | 8
Segment adjusted operating income (loss) | 10 | 4 | 0 | 4
Realized gains (losses) on investments | Revenues |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Realized gains (losses) on investments | (28) | 4 | (25) | 1
Realized gains (losses) on investments | Expenses |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Realized gains (losses) on investments | 0 | 0 | 0 | 0
Realized gains (losses) on investments | Equity in Earnings (Losses) of Investees |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Realized gains (losses) on investments | 0 | 0 | 0 | 0
Realized gains (losses) on investments | Provision (Benefit) for Income Taxes |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Realized gains (losses) on investments | 0 | 0 | 0 | 0
Realized gains (losses) on investments | Nonredeemable Noncontrolling Interests |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Realized gains (losses) on investments | 0 | 0 | 0 | 0
Realized gains (losses) on investments | Net Income (Loss) Attributable to AGL |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Realized gains (losses) on investments | (28) | 4 | (25) | 1
Non-credit impairment-related unrealized fair value gains (losses) on credit derivatives | Revenues |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Non-credit impairment-related unrealized fair value gains (losses) on credit derivatives | 6 | (37) | (1) | (59)
Non-credit impairment-related unrealized fair value gains (losses) on credit derivatives | Expenses |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Non-credit impairment-related unrealized fair value gains (losses) on credit derivatives | 0 | (6) | (4) | (9)
Non-credit impairment-related unrealized fair value gains (losses) on credit derivatives | Equity in Earnings (Losses) of Investees |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Non-credit impairment-related unrealized fair value gains (losses) on credit derivatives | 0 | 0 | 0 | 0
Non-credit impairment-related unrealized fair value gains (losses) on credit derivatives | Provision (Benefit) for Income Taxes |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Non-credit impairment-related unrealized fair value gains (losses) on credit derivatives | 0 | 0 | 0 | 0
Non-credit impairment-related unrealized fair value gains (losses) on credit derivatives | Nonredeemable Noncontrolling Interests |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Non-credit impairment-related unrealized fair value gains (losses) on credit derivatives | 0 | 0 | 0 | 0
Non-credit impairment-related unrealized fair value gains (losses) on credit derivatives | Net Income (Loss) Attributable to AGL |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Non-credit impairment-related unrealized fair value gains (losses) on credit derivatives | 6 | (31) | 3 | (50)
Fair value gains (losses) on CCS | Revenues |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Fair value gains (losses) on committed capital securities | 10 | (6) | 11 | (25)
Fair value gains (losses) on CCS | Expenses |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Fair value gains (losses) on committed capital securities |  | 0 |  | 0
Fair value gains (losses) on CCS | Equity in Earnings (Losses) of Investees |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Fair value gains (losses) on committed capital securities |  | 0 | 0 | 0
Fair value gains (losses) on CCS | Provision (Benefit) for Income Taxes |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Fair value gains (losses) on committed capital securities |  | 0 | 0 | 0
Fair value gains (losses) on CCS | Nonredeemable Noncontrolling Interests |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Fair value gains (losses) on committed capital securities |  | 0 | 0 | 0
Fair value gains (losses) on CCS | Net Income (Loss) Attributable to AGL |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Fair value gains (losses) on committed capital securities | 10 | (6) | 11 | (25)
Foreign exchange gains (losses) on remeasurement of premiums receivable and loss and LAE reserves | Revenues |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Foreign exchange gains (losses) on remeasurement of premiums receivable and loss and LAE reserves | (73) | 5 | (102) | 6
Foreign exchange gains (losses) on remeasurement of premiums receivable and loss and LAE reserves | Expenses |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Foreign exchange gains (losses) on remeasurement of premiums receivable and loss and LAE reserves | 0 | 0 | 0 | 0
Foreign exchange gains (losses) on remeasurement of premiums receivable and loss and LAE reserves | Equity in Earnings (Losses) of Investees |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Foreign exchange gains (losses) on remeasurement of premiums receivable and loss and LAE reserves | 0 | 0 | 0 | 0
Foreign exchange gains (losses) on remeasurement of premiums receivable and loss and LAE reserves | Provision (Benefit) for Income Taxes |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Foreign exchange gains (losses) on remeasurement of premiums receivable and loss and LAE reserves | 0 | 0 | 0 | 0
Foreign exchange gains (losses) on remeasurement of premiums receivable and loss and LAE reserves | Nonredeemable Noncontrolling Interests |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Foreign exchange gains (losses) on remeasurement of premiums receivable and loss and LAE reserves | 0 | 0 | 0 | 0
Foreign exchange gains (losses) on remeasurement of premiums receivable and loss and LAE reserves | Net Income (Loss) Attributable to AGL |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Foreign exchange gains (losses) on remeasurement of premiums receivable and loss and LAE reserves | (73) | 5 | (102) | 6
Tax effect | Revenues |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Tax effect | 0 | 0 | 0 | 0
Tax effect | Expenses |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Tax effect | 0 | 0 | 0 | 0
Tax effect | Equity in Earnings (Losses) of Investees |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Tax effect | 0 | 0 | 0 | 0
Tax effect | Provision (Benefit) for Income Taxes |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Tax effect | (8) | (6) | (12) | (14)
Tax effect | Nonredeemable Noncontrolling Interests |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Tax effect | 0 | 0 | 0 | 0
Tax effect | Net Income (Loss) Attributable to AGL |  |  |  |
Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] |  |  |  |
Tax effect | $ 8 | $ 6 | $ 12 | $ 14

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