Debt (Tables)

3 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Schedule of Debt

The Company had outstanding debt as follows:

	December 31, 2017							September 30, 2017
	Principal Amount		Unamortized Discounts and Debt Issuance Costs			Carrying Amount		Principal Amount		Unamortized Discounts and Debt Issuance Costs			Carrying Amount		Effective Interest Rate
	(in millions, except percentages)
1.20% Senior Notes due December 2017 (the "2017 Notes")	$	—	$	—		$	—	$	1,750	$	(1	)	$	1,749	1.37	%
Total current maturities of long-term debt	—		—			—		1,750		(1		)	1,749
2.20% Senior Notes due December 2020	3,000		(9		)	2,991		3,000		(10		)	2,990		2.30	%
2.15% Senior Notes due September 2022	1,000		(7		)	993		1,000		(7		)	993		2.30	%
2.80% Senior Notes due December 2022	2,250		(10		)	2,240		2,250		(10		)	2,240		2.89	%
3.15% Senior Notes due December 2025	4,000		(31		)	3,969		4,000		(33		)	3,967		3.26	%
2.75% Senior Notes due September 2027	750		(10		)	740		750		(10		)	740		2.91	%
4.15% Senior Notes due December 2035	1,500		(14		)	1,486		1,500		(15		)	1,485		4.23	%
4.30% Senior Notes due December 2045	3,500		(38		)	3,462		3,500		(37		)	3,463		4.37	%
3.65% Senior Notes due September 2047	750		(10		)	740		750		(10		)	740		3.73	%
Total long-term debt	16,750		(129		)	16,621		16,750		(132		)	16,618
Total debt	$	16,750	$	(129	)	$	16,621	$	18,500	$	(133	)	$	18,367