Employee Benefit Plans (Estimated Future Benefit Payments) (Details) $ in Millions	Dec. 31, 2019 USD ($)
Defined Benefit Plan Disclosure [Line Items]
2020	$ 15
2021	12
2022	12
2023	13
2024	13
Thereafter	70
Total	135
Other Plan Benefits
Defined Benefit Plan Disclosure [Line Items]
2020	2
2021	2
2022	2
2023	2
2024	2
Thereafter	9
Total	19
IMTT \| DB Plans Benefits
Defined Benefit Plan Disclosure [Line Items]
2020	10
2021	7
2022	7
2023	8
2024	8
Thereafter	45
Total	85
Hawaii Gas Business \| MIC Hawaii \| DB Plans Benefits
Defined Benefit Plan Disclosure [Line Items]
2020	3
2021	3
2022	3
2023	3
2024	3
Thereafter	16
Total	$ 31

Defined Benefit Plan, Total Expected Future Benefit Payments

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Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest 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 1
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year.

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