Debt - Maturities of Long-Term Debt (Details) $ in Millions	Sep. 30, 2019 USD ($)
Debt Instrument [Line Items]
Total	$ 1,262
2020	18
2021	16
2022	722
2023	22
2024	154
Thereafter	$ 330
5.375% Notes
Debt Instrument [Line Items]
Percentage of contractual interest rate	5.375%
4.875% Notes
Debt Instrument [Line Items]
Percentage of contractual interest rate	4.875%
1.125% Convertible Notes
Debt Instrument [Line Items]
Percentage of contractual interest rate	1.125%
Senior Notes \| 5.375% Notes
Debt Instrument [Line Items]
Percentage of contractual interest rate	5.375%
Total	$ 700
2020	0
2021	0
2022	700
2023	0
2024	0
Thereafter	$ 0
Senior Notes \| 4.875% Notes
Debt Instrument [Line Items]
Percentage of contractual interest rate	4.875%
Total	$ 330
2020	0
2021	0
2022	0
2023	0
2024	0
Thereafter	330
Term Loan Facility \| Term Loan Facility
Debt Instrument [Line Items]
Total	220
2020	6
2021	16
2022	22
2023	22
2024	154
Thereafter	$ 0
Convertible Notes \| 1.125% Convertible Notes
Debt Instrument [Line Items]
Percentage of contractual interest rate	1.125%
Total	$ 12
2020	12
2021	0
2022	0
2023	0
2024	0
Thereafter	$ 0

Long-term Debt, Maturities, Repayments of Principal after Year Six

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- Definition

Long-term Debt, Maturities, Repayments of Principal in Year Six

+ References

No definition available.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
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- Definition

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

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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