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Employee Benefits Schedule of Fair Value, Assets (Details) - USD ($) $ in Millions | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | --- | ---
Defined Benefit Plan Disclosure [Line Items] |  |  |
Money Market Funds, at Carrying Value | $ 7 | $ 25 |
Equity securities: |  |  |
Domestic | 67 | 83 |
Defined Benefit Plan, Plan Assets, Amount |  | 629 |
Financial Instruments, Owned, at Fair Value | 7 | 25 |
Other Postretirement Benefit Plans assets: [Abstract] |  |  |
Money market funds |  | 3 |
Domestic equity securities - Other postretirement benefit plan assets at fair value |  | 3 |
International equity securities - other post retirement assets at fair value |  | 10 |
Private Equity Funds, US [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Money Market Funds, at Carrying Value | 5 | 5 |
Investments, Fair Value Disclosure | 11 | 13 |
Equity Securities [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Investments, Fair Value Disclosure | 463 | 528 |
Fair Value, Inputs, Level 1 [Member] |  |  |
Equity securities: |  |  |
Domestic | 67 | 83 |
Private equity funds | 0 | 0 |
Defined Benefit Plan, Plan Assets, Amount | 67 | 83 |
Financial Instruments, Owned, at Fair Value | 128 | 43 |
Other Postretirement Benefit Plans assets: [Abstract] |  |  |
Money market funds | 3 | 3 |
Domestic equity securities - Other postretirement benefit plan assets at fair value | 0 | 0 |
International equity securities - other post retirement assets at fair value | 8 | 10 |
Other post retirement benefit plan assets total | 11 | 13 |
Fair Value, Inputs, Level 2 [Member] |  |  |
Equity securities: |  |  |
Domestic | 0 | 0 |
Private equity funds | 0 | 0 |
Defined Benefit Plan, Plan Assets, Amount | 0 | 0 |
Financial Instruments, Owned, at Fair Value | 45 | 19 |
Other Postretirement Benefit Plans assets: [Abstract] |  |  |
Money market funds | 0 | 0 |
Domestic equity securities - Other postretirement benefit plan assets at fair value | 3 | 3 |
International equity securities - other post retirement assets at fair value | 0 | 0 |
Other post retirement benefit plan assets total | 8 | 8 |
Fair Value, Inputs, Level 3 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Money Market Funds, at Carrying Value | 0 |  |
Equity securities: |  |  |
Domestic | 0 | 0 |
Private equity funds | 0 | 0 |
Defined Benefit Plan, Plan Assets, Amount | 0 | 0 |
Financial Instruments, Owned, at Fair Value | 3 | 0 |
Other Postretirement Benefit Plans assets: [Abstract] |  |  |
Money market funds | 0 | 0 |
Domestic equity securities - Other postretirement benefit plan assets at fair value | 0 | 0 |
International equity securities - other post retirement assets at fair value | 0 | 0 |
Other post retirement benefit plan assets total | 0 | 0 |
Pension Plan [Member] |  |  |
Equity securities: |  |  |
Defined Benefit Plan, Plan Assets, Amount | 546 | 629 | $ 559
Financial Instruments, Owned, at Fair Value | 479 | 546 |
Other Postretirement Benefit Plans [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Money Market Funds, at Carrying Value | 4 | 4 |
Investments, Fair Value Disclosure | 7 | 8 |
Equity securities: |  |  |
Defined Benefit Plan, Plan Assets, Amount | 30 | 33 | $ 30
Financial Instruments, Owned, at Fair Value | 11 | $ 12 |
Other Postretirement Benefit Plans assets: [Abstract] |  |  |
Money market funds | 3 |  |
Domestic equity securities - Other postretirement benefit plan assets at fair value | 3 |  |
International equity securities - other post retirement assets at fair value | $ 8 |  |

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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=108410482&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=108410482&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=108410482&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=112275985&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=108410482&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=108410482&loc=d3e1928-114920 + Details
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