v3.20.4

Pension And Postretirement Benefits (Fair Value Assets Measured On Recurring Basis Unobservable Input (Level 3) Reconciliation) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019
Pension Assets |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value of plan assets at beginning of year | $ 53,530 | $ 51,681
Fair value of plan assets at end of year | 54,606 | 53,530
Pension Assets | Level 3 |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value of plan assets at beginning of year | 11,639 | 11,333
Realized gains (losses) | 105 | 64
Unrealized gains (losses) | (175) | 103
Transfers in | 91 | 147
Transfers out | (3) | (6)
Purchases | 9,338 | 235
Sales | (12,605) | (237)
Fair value of plan assets at end of year | 8,390 | 11,639
Pension Assets | Equity securities | Level 3 |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value of plan assets at beginning of year | 8,816 | 8,750
Realized gains (losses) | (150) | 0
Unrealized gains (losses) | 3 | 58
Transfers in | 4 | 8
Transfers out | 0 | 0
Purchases | 9,114 | 0
Sales | (11,994) | 0
Fair value of plan assets at end of year | 5,793 | 8,816
Pension Assets | Fixed Income Funds | Level 3 |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value of plan assets at beginning of year | 6 | 4
Realized gains (losses) | 0 | 0
Unrealized gains (losses) | 0 | 0
Transfers in | 51 | 5
Transfers out | (3) | (6)
Purchases | 1 | 7
Sales | (2) | (4)
Fair value of plan assets at end of year | 53 | 6
Pension Assets | Real Estate and Real Assets |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value of plan assets at beginning of year | 2,817 |
Fair value of plan assets at end of year | 2,544 | 2,817
Pension Assets | Real Estate and Real Assets | Level 3 |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value of plan assets at beginning of year | 2,817 | 2,579
Realized gains (losses) | 255 | 64
Unrealized gains (losses) | (178) | 45
Transfers in | 36 | 134
Transfers out | 0 | 0
Purchases | 223 | 228
Sales | (609) | (233)
Fair value of plan assets at end of year | 2,544 | 2,817
Postretirement Assets |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value of plan assets at beginning of year | 4,145 | 4,277
Fair value of plan assets at end of year | 3,843 | 4,145
Postretirement Assets | Level 3 |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value of plan assets at beginning of year | 32 | 13
Transfers in | 3 | 28
Transfers out | (11) | (1)
Sales | (20) | (8)
Fair value of plan assets at end of year | 4 | 32
Postretirement Assets | Equity securities | Level 3 |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value of plan assets at beginning of year | 0 | 1
Transfers in | 0 | 0
Transfers out | 0 | 0
Sales | 0 | (1)
Fair value of plan assets at end of year | 0 | 0
Postretirement Assets | Fixed Income Funds | Level 3 |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value of plan assets at beginning of year | 32 | 12
Transfers in | 3 | 28
Transfers out | (11) | (1)
Sales | (20) | (7)
Fair value of plan assets at end of year | 4 | 32
Postretirement Assets | Real Estate and Real Assets | Level 3 |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value of plan assets at beginning of year | 0 | 0
Transfers in | 0 | 0
Transfers out | 0 | 0
Sales | 0 | 0
Fair value of plan assets at end of year | $ 0 | $ 0

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