Long-term and Short-term Debt - Narrative (Details) - USD ($)	Mar. 31, 2020	Sep. 30, 2019
Short-term Debt [Abstract]
Commercial paper borrowings outstanding	$ 58,000,000.0	$ 0
Short-term debt	$ 81,500,000	$ 0
Weighted average interest rate of commercial paper outstanding	2.40%
2.050% notes, payable in March 2020
Long-term Debt, Current Maturities [Abstract]
Long-term debt issued	$ 300,000,000.0
Stated interest rate	2.05%
Schlumberger
Short-term Debt [Abstract]
Short-term debt	$ 23,500,000

Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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Weighted average interest rate of short-term debt outstanding calculated at point in time.

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