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Debt and Financing Arrangements - Long-term Debt (Details) - USD ($) $ in Millions		12 Months Ended
	May 29, 2017	Sep. 30, 2019	May 06, 2019	Sep. 30, 2018	Aug. 19, 2016
Debt Instrument [Line Items]
Capital lease obligations		$ 0		$ 2
Less: debt issuance costs		(56)		(32)
Gross long-term debt		3,716		3,424
Less: current portion		8		2
Net long-term debt		3,708		3,422
EURIBOR
Debt Instrument [Line Items]
Basis spread (as percent)	0.90%
Revolving credit facility \| Term Loan A - LIBOR plus 1.75% due in 2021
Debt Instrument [Line Items]
Long-term debt, gross		$ 0		1,200
Revolving credit facility \| Term Loan A - LIBOR plus 1.75% due in 2021 \| LIBOR
Debt Instrument [Line Items]
Interest rate (as percent)		1.75%
Revolving credit facility \| Term Loan B - LIBOR plus 4.25% due in 2024
Debt Instrument [Line Items]
Long-term debt, gross		$ 798		0
Revolving credit facility \| Term Loan B - LIBOR plus 4.25% due in 2024 \| LIBOR
Debt Instrument [Line Items]
Interest rate (as percent)		4.25%
Unsecured debt \| 4.875% Notes due in 2026
Debt Instrument [Line Items]
Long-term debt, gross		$ 900		900
Interest rate (as percent)		4.875%			4.875%
Unsecured debt \| 3.50% Notes due in 2024
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,094		1,162
Interest rate (as percent)		3.50%			3.50%
Unsecured debt \| 7.00% Notes due in 2026
Debt Instrument [Line Items]
Long-term debt, gross		$ 800		0
Interest rate (as percent)		7.00%	7.00%
Unsecured debt \| European Investment Bank Loan due in 2022
Debt Instrument [Line Items]
Long-term debt, gross		$ 180		$ 192
Unsecured debt \| European Investment Bank Loan due in 2022 \| EURIBOR
Debt Instrument [Line Items]
Basis spread (as percent)		0.90%