| Components of comprehensive income (loss), net of tax |
Changes in each component for the three and nine months ended September 30, 2021 and 2020 were as follows: | | | | | | | | | | | | | | | | | | | | | | | | | | | | Three Months Ended September 30, 2021 (Millions), net of tax | | Net Unrealized Gains (Losses) on Debt Securities | | Foreign Currency Translation Adjustment Gains (Losses) | | Net Unrealized Pension and Other Postretirement Benefit Gains (Losses) | | Accumulated Other Comprehensive Income (Loss) | | Balances as of June 30, 2021 | | $ | 42 | | | $ | (2,227) | | | $ | (696) | | | $ | (2,881) | | | Net unrealized losses | | (8) | | | — | | | — | | | (8) | | | Net translation on investments in foreign operations | | — | | | (238) | | | — | | | (238) | | | Net hedges of investments in foreign operations | | — | | | 155 | | | — | | | 155 | | | Pension and other postretirement benefits | | — | | | — | | | 9 | | | 9 | | | Net change in accumulated other comprehensive income (loss) | | (8) | | | (83) | | | 9 | | | (82) | | | Balances as of September 30, 2021 | | $ | 34 | | | $ | (2,310) | | | $ | (687) | | | $ | (2,963) | |
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Nine Months Ended September 30, 2021 (Millions), net of tax | | Net Unrealized Gains (Losses) on Debt Securities | | Foreign Currency Translation Adjustment Gains (Losses) | | Net Unrealized Pension and Other Postretirement Benefit Gains (Losses) | | Accumulated Other Comprehensive Income (Loss) | | Balances as of December 31, 2020 | | $ | 65 | | | $ | (2,229) | | | $ | (731) | | | $ | (2,895) | | | Net unrealized losses | | (31) | | | — | | | — | | | (31) | | | Net translation on investments in foreign operations | | — | | | (134) | | | — | | | (134) | | | Net hedges of investments in foreign operations | | — | | | 53 | | | — | | | 53 | | | Pension and other postretirement benefits | | — | | | — | | | 44 | | | 44 | | | Net change in accumulated other comprehensive income (loss) | | (31) | | | (81) | | | 44 | | | (68) | | | Balances as of September 30, 2021 | | $ | 34 | | | $ | (2,310) | | | $ | (687) | | | $ | (2,963) | |
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Three Months Ended September 30, 2020 (Millions), net of tax | | Net Unrealized Gains (Losses) on Debt Securities | | Foreign Currency Translation Adjustment Gains (Losses) | | Net Unrealized Pension and Other Postretirement Benefit Gains (Losses) | | Accumulated Other Comprehensive Income (Loss) | | Balances as of June 30, 2020 | | $ | 85 | | | $ | (2,388) | | | $ | (608) | | | $ | (2,911) | | | Net unrealized losses | | (9) | | | — | | | — | | | (9) | | | | | | | | | | | | Net translation on investments in foreign operations | | — | | | 210 | | | — | | | 210 | | | Net hedges of investments in foreign operations | | — | | | (170) | | | — | | | (170) | | | Pension and other postretirement benefits | | — | | | — | | | 8 | | | 8 | | | Net change in accumulated other comprehensive income (loss) | | (9) | | | 40 | | | 8 | | | 39 | | | Balances as of September 30, 2020 | | $ | 76 | | | $ | (2,348) | | | $ | (600) | | | $ | (2,872) | |
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Nine Months Ended September 30, 2020 (Millions), net of tax | | Net Unrealized Gains (Losses) on Debt Securities | | Foreign Currency Translation Adjustment Gains (Losses) | | Net Unrealized Pension and Other Postretirement Benefit Gains (Losses) | | Accumulated Other Comprehensive Income (Loss) | | Balances as of December 31, 2019 | | $ | 33 | | | $ | (2,189) | | | $ | (581) | | | $ | (2,737) | | | Net unrealized gains | | 43 | | | — | | | — | | | 43 | | | Decrease due to amounts reclassified into earnings | | — | | | (3) | | | — | | | (3) | | | Net translation on investments in foreign operations | | — | | | (379) | | | — | | | (379) | | | Net hedges of investments in foreign operations | | — | | | 223 | | | — | | | 223 | | | Pension and other postretirement benefits | | — | | | — | | | (19) | | | (19) | | | Net change in accumulated other comprehensive income (loss) | | 43 | | | (159) | | | (19) | | | (135) | | | Balances as of September 30, 2020 | | $ | 76 | | | $ | (2,348) | | | $ | (600) | | | $ | (2,872) | |
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