Debt Schedule (Details) - USD ($) $ in Millions	Dec. 31, 2018	Sep. 30, 2018
Debt Instrument [Line Items]
Capital lease and other obligations	$ 26	$ 30
Total debt	8,961	10,082
Less current portion	326	567
Noncurrent portion	$ 8,635	9,515
Senior notes due September 2019, 5.625%
Debt Instrument [Line Items]
Coupon Rate	5.625%
Senior Notes and Debentures	$ 221	550
Senior notes due December 2019, 2.750%
Debt Instrument [Line Items]
Coupon Rate	2.75%
Senior Notes and Debentures	$ 90	252
Senior notes due March 2021, 4.500%
Debt Instrument [Line Items]
Coupon Rate	4.50%
Senior Notes and Debentures	$ 498	497
Senior notes due December 2021, 3.875%
Debt Instrument [Line Items]
Coupon Rate	3.875%
Senior Notes and Debentures	$ 596	596
Senior notes due February 2022, 2.250%
Debt Instrument [Line Items]
Coupon Rate	2.25%
Senior Notes and Debentures	$ 49	102
Senior notes due June 2022, 3.125%
Debt Instrument [Line Items]
Coupon Rate	3.125%
Senior Notes and Debentures	$ 194	194
Senior notes due March 2023, 3.250%
Debt Instrument [Line Items]
Coupon Rate	3.25%
Senior Notes and Debentures	$ 181	181
Senior notes due September 2023, 4.250%
Debt Instrument [Line Items]
Coupon Rate	4.25%
Senior Notes and Debentures	$ 1,240	1,239
Senior notes due April 2024, 3.875%
Debt Instrument [Line Items]
Coupon Rate	3.875%
Senior Notes and Debentures	$ 489	488
Senior notes due October 2026, 3.450%
Debt Instrument [Line Items]
Coupon Rate	3.45%
Senior Notes and Debentures	$ 123	474
Senior debentures due December 2034, 4.850%
Debt Instrument [Line Items]
Coupon Rate	4.85%
Senior Notes and Debentures	$ 86	281
Senior debentures due April 2036, 6.875%
Debt Instrument [Line Items]
Coupon Rate	6.875%
Senior Notes and Debentures	$ 1,068	1,068
Senior debentures due October 2037, 6.750%
Debt Instrument [Line Items]
Coupon Rate	6.75%
Senior Notes and Debentures	$ 75	75
Senior debentures due February 2042, 4.500%
Debt Instrument [Line Items]
Coupon Rate	4.50%
Senior Notes and Debentures	$ 45	62
Senior debentures due March 2043, 4.375%
Debt Instrument [Line Items]
Coupon Rate	4.375%
Senior Notes and Debentures	$ 1,103	1,102
Senior debentures due June 2043, 4.875%
Debt Instrument [Line Items]
Coupon Rate	4.875%
Senior Notes and Debentures	$ 18	32
Senior debentures due September 2043, 5.850%
Debt Instrument [Line Items]
Coupon Rate	5.85%
Senior Notes and Debentures	$ 1,230	1,230
Senior debentures due April 2044, 5.250%
Debt Instrument [Line Items]
Coupon Rate	5.25%
Senior Notes and Debentures	$ 345	345
Junior subordinated debentures due February 2057, 5.875%
Debt Instrument [Line Items]
Coupon Rate	5.875%
Junior Subordinated Debentures	$ 642	642
Junior subordinated debentures due February 2057, 6.250%
Debt Instrument [Line Items]
Coupon Rate	6.25%
Junior Subordinated Debentures	$ 642	$ 642

Amount of short-term debt and current maturity of long-term debt and capital lease obligations due within one year or the normal operating cycle, if longer.

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