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Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income, Net of Tax (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2021 | Mar. 31, 2020
Deferred Taxes |  |
Balance | $ (39) | $ (160)
Changes in value | (3) | 15
Amounts reclassified to earnings | (1) | 1
Balance | (43) | (144)
Total |  |
Balance | 5,960 | 11,531
Changes in value | 9 | (50)
Amounts reclassified to earnings | 4 | (3)
Balance | 5,206 | 9,418
Pension and Other Postretirement Liabilities |  |
Before Tax |  |
Balance | (1,102) | (560)
Changes in value | 13 | (49)
Amounts reclassified to earnings | 5 | (4)
Balance | (1,084) | (613)
Investments and Other |  |
Before Tax |  |
Balance | 2 | 2
Changes in value | (1) | (16)
Amounts reclassified to earnings | 0 | 0
Balance | 1 | (14)
Accumulated Other Comprehensive Income (Loss) |  |
Total |  |
Balance | (1,139) | (718)
Balance | $ (1,126) | $ (771)

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