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Pension and Other Postretirement Benefit Plans - Summary of Changes in Fair Value of Company's Level 3 Pension Plan Assets (Details) - Pension Benefits - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020
Level 3 |  |
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] |  |
Fair value of plan assets January 1 | $ 942 |
Actual return on plan assets: |  |
Fair value of plan assets December 31 | 943 | $ 942
United States |  |
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] |  |
Fair value of plan assets January 1 | 12,672 | 11,361
Actual return on plan assets: |  |
Fair value of plan assets December 31 | 13,067 | 12,672
United States | Other |  |
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] |  |
Fair value of plan assets January 1 | 7 |
Actual return on plan assets: |  |
Fair value of plan assets December 31 | 8 | 7
United States | Level 3 |  |
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] |  |
Fair value of plan assets January 1 | 7 | 9
Actual return on plan assets: |  |
Relating to assets still held at December 31 | (5) | (5)
Relating to assets sold during the year | 7 | 5
Purchases and sales, net | (3) | (2)
Fair value of plan assets December 31 | 6 | 7
United States | Level 3 | Insurance Contracts |  |
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] |  |
Fair value of plan assets January 1 | 0 | 0
Actual return on plan assets: |  |
Relating to assets still held at December 31 | 0 | 0
Relating to assets sold during the year | 0 | 0
Purchases and sales, net | 0 | 0
Fair value of plan assets December 31 | 0 | 0
United States | Level 3 | Real Estate |  |
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] |  |
Fair value of plan assets January 1 | 0 | 0
Actual return on plan assets: |  |
Relating to assets still held at December 31 | 0 | 0
Relating to assets sold during the year | 0 | 0
Purchases and sales, net | 0 | 0
Fair value of plan assets December 31 | 0 | 0
United States | Level 3 | Other |  |
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] |  |
Fair value of plan assets January 1 | 7 | 9
Actual return on plan assets: |  |
Relating to assets still held at December 31 | (5) | (5)
Relating to assets sold during the year | 7 | 5
Purchases and sales, net | (3) | (2)
Fair value of plan assets December 31 | 6 | 7
International |  |
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] |  |
Fair value of plan assets January 1 | 12,009 | 10,135
Actual return on plan assets: |  |
Fair value of plan assets December 31 | 12,195 | 12,009
International | Insurance Contracts |  |
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] |  |
Fair value of plan assets January 1 | 978 |
Actual return on plan assets: |  |
Fair value of plan assets December 31 | 982 | 978
International | Real Estate |  |
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] |  |
Fair value of plan assets January 1 | 16 |
Actual return on plan assets: |  |
Fair value of plan assets December 31 | 17 | 16
International | Other |  |
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] |  |
Fair value of plan assets January 1 | 5 |
Actual return on plan assets: |  |
Fair value of plan assets December 31 | 2 | 5
International | Level 3 |  |
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] |  |
Fair value of plan assets January 1 | 935 | 851
Actual return on plan assets: |  |
Relating to assets still held at December 31 | (34) | 103
Purchases and sales, net | (42) | (17)
Transfers in (out) of Level 3 | 78 | (2)
Fair value of plan assets December 31 | 937 | 935
International | Level 3 | Insurance Contracts |  |
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] |  |
Fair value of plan assets January 1 | 935 | 851
Actual return on plan assets: |  |
Relating to assets still held at December 31 | (34) | 103
Purchases and sales, net | (42) | (17)
Transfers in (out) of Level 3 | 78 | (2)
Fair value of plan assets December 31 | 937 | 935
International | Level 3 | Real Estate |  |
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] |  |
Fair value of plan assets January 1 | 0 | 0
Actual return on plan assets: |  |
Relating to assets still held at December 31 | 0 | 0
Purchases and sales, net | 0 | 0
Transfers in (out) of Level 3 | 0 | 0
Fair value of plan assets December 31 | 0 | 0
International | Level 3 | Other |  |
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] |  |
Fair value of plan assets January 1 | 0 | 0
Actual return on plan assets: |  |
Relating to assets still held at December 31 | 0 |
Purchases and sales, net | 0 | 0
Transfers in (out) of Level 3 | 0 | 0
Fair value of plan assets December 31 | $ 0 | $ 0

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