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Debt - Schedule of Debt (Details) £ in Millions, $ in Millions	Sep. 30, 2021 USD ($)	Sep. 30, 2021 EUR (€)	Sep. 30, 2021 GBP (£)	Apr. 01, 2021	Mar. 31, 2021 USD ($)
Short-term debt and current maturities of long-term debt
Commercial paper	$ 232				$ 213
Current maturities of long-term debt	179				556
Current maturities of finance lease liabilities	334				398
Short-term debt and current maturities of long-term debt	745				1,167
Long-term debt, net of current maturities
Finance lease liabilities	729				894
Long-term debt	4,876				5,299
Less: current maturities	513				954
Long-term debt, net of current maturities	$ 4,363				4,345
Finance lease liabilities \| Minimum
Debt Information [Abstract]
Effective interest rate	0.35%	0.35%	0.35%
Finance lease liabilities \| Maximum
Debt Information [Abstract]
Effective interest rate	17.68%	17.68%	17.68%
Borrowings for assets acquired under long-term financing
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 441				672
Borrowings for assets acquired under long-term financing \| Minimum
Debt Information [Abstract]
Effective interest rate	0.00%	0.00%	0.00%
Borrowings for assets acquired under long-term financing \| Maximum
Debt Information [Abstract]
Effective interest rate	6.78%	6.78%	6.78%
Mandatorily redeemable preferred stock outstanding
Debt Information [Abstract]
Effective interest rate	6.00%	6.00%	6.00%
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 63				63
Other borrowings
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 5				5
Senior Notes Due 2028 \| Senior notes
Debt Information [Abstract]
Face amount \| €		€ 750,000,000
Effective interest rate	0.45%	0.45%	0.45%
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 862				0
Senior Notes Due 2032 \| Senior notes
Debt Information [Abstract]
Face amount \| €		€ 600,000,000
Effective interest rate	0.95%	0.95%	0.95%
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 688				0
Senior Notes Due 2027 \| Senior notes
Debt Information [Abstract]
Face amount	$ 700
Effective interest rate	1.80%	1.80%	1.80%
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 694				0
Senior Notes Due 2029 \| Senior notes
Debt Information [Abstract]
Face amount	$ 650
Effective interest rate	2.375%	2.375%	2.375%
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 644				0
Term Loan Payable, EUR, Due 2023-2024 \| Term loan
Debt Information [Abstract]
Effective interest rate	0.80%	0.80%	0.80%
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 0				469
Senior Notes Due 2023 \| Senior notes
Debt Information [Abstract]
Face amount	$ 274
Effective interest rate	4.45%	4.45%	4.45%
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 0				154
Senior Notes, Due 2023 \| Senior notes
Debt Information [Abstract]
Face amount	$ 171
Effective interest rate	4.45%	4.45%	4.45%	0.0445%
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 0				165
Senior Notes Due 2025 \| Senior notes
Debt Information [Abstract]
Face amount	$ 500
Effective interest rate	4.25%	4.25%	4.25%
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 0				504
Senior Notes, Due 2026 \| Senior notes
Debt Information [Abstract]
Face amount	$ 500
Effective interest rate	4.125%	4.125%	4.125%
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 0				496
Senior Notes Due 2025 \| Senior notes
Debt Information [Abstract]
Face amount \| £			£ 250
Effective interest rate	2.75%	2.75%	2.75%
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 0				343
Senior Notes Due 2026 \| Senior notes
Debt Information [Abstract]
Face amount \| €		€ 650,000,000
Effective interest rate	1.75%	1.75%	1.75%
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 750				760
Senior Notes Due 2028 \| Senior notes
Debt Information [Abstract]
Face amount	$ 500
Effective interest rate	4.75%	4.75%	4.75%
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 0				506
Senior Notes Due 2030 \| Senior notes
Debt Information [Abstract]
Face amount	$ 234
Effective interest rate	7.45%	7.45%	7.45%
Long-term debt, net of current maturities
Long-term debt, net of current maturities	$ 0				$ 268
Commercial paper
Long-term debt, net of current maturities
Amount of multi-year committed revolving credit facility \| €		€ 1,000,000,000
Commercial paper \| Minimum
Debt Information [Abstract]
Weighted average interest rate	(0.43%)	(0.43%)	(0.43%)
Commercial paper \| Maximum
Debt Information [Abstract]
Weighted average interest rate	(0.15%)	(0.15%)	(0.15%)
Current maturities of finance lease liabilities \| Minimum
Debt Information [Abstract]
Effective interest rate	0.35%	0.35%	0.35%
Current maturities of finance lease liabilities \| Maximum
Debt Information [Abstract]
Effective interest rate	17.68%	17.68%	17.68%