v3.20.1

Pension and Other Postretirement Benefits - Narrative (Details) - USD ($) $ in Millions |  | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jan. 01, 2020 | Mar. 31, 2020 | Mar. 31, 2019 | Dec. 31, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |
Retirement plans, liability | $ 1,920 |  |  |
Retirement plans, current liability | 60 |  |  |
Retirement plans, benefit obligation | 4,255 |  |  |
Retirement plans, plan assets | 2,335 |  |  |
Establishment of retirement plans, AOCI | $ 1,752 |  |  |
Net periodic benefit cost |  | $ 26 |  |
Service cost |  | 6 |  |
Multiemployer contribution expense |  |  | $ 28 |
Forecast |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |
Net periodic benefit cost |  |  |  | $ 100
Service cost |  |  |  | $ 25
Pension benefits |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |
Net periodic benefit cost |  | 21 | 1 |
Service cost |  | 5 | 0 |
Multiemployer contribution expense |  | 0 | 16 |
Expected employer contributions, 2020 |  | 255 |  |
Other postretirement benefits |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |
Net periodic benefit cost |  | 6 | 0 |
Service cost |  | 1 | 0 |
Multiemployer contribution expense |  | 0 | $ 5 |
Expected employer contributions, 2020 |  | $ 55 |  |

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- Definition Amount of contributions received and expected to be received by defined benefit plan from employer in current fiscal year. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920 + Details
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- Definition Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 6: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
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