Debt - Schedule of Long-term Debt (Details) $ / shares in Units, shares in Millions, $ in Millions			1 Months Ended	3 Months Ended
		Dec. 01, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 03, 2015 USD ($) integer shares $ / shares		Sep. 03, 2015 USD ($)
Long-term Debt, by Current and Noncurrent [Abstract]
Current debt				$ 1,051		$ 1,089
Long-term debt				6,326		6,252
Debt				$ 7,377		7,341
Convertible Debt Issuances [Abstract]
Share Price (in dollars per share) | $ / shares				$ 15.61
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Remainder of 2016				$ 241
2017				176
2018				129
2019				91
2020				32
2021 and thereafter				110
Capital Leases, Future Minimum Payments, Interest Included in Payments				(70)
Capital Lease Obligations				709
Reorganization obligation [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Current debt				160		161
Long-term debt				695		701
Debt				$ 855		862
Effective interest rate (in thousandths)				6.25%
Capital lease obligations [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Current debt	[1]			$ 273		326
Long-term debt	[1]			436		466
Debt	[1]			$ 709		$ 792
Weighted average effective interest rate (in thousandths)				3.80%		3.70%
Leases, Capital [Abstract]
Capital Lease Obligations Incurred				$ 20
Percentage, Incurred in Current Period				5.00%
Capital lease obligations [Member] | Sales-leaseback transactions [Member] | Subsequent Event [Member]
Leases, Capital [Abstract]
Capital Lease Obligations Incurred			$ 424
Percentage, Incurred in Current Period			2.70%
Secured Debt [Member] | 1.258% senior notes [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Current debt				$ 87		$ 87
Long-term debt				219		217
Debt				$ 306		304
Stated interest rate (in thousandths)				1.258%
Effective interest rate (in thousandths)				1.97%
Corporate bonds [Member] | 2022 senior notes [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Current debt				$ 0		0
Long-term debt				589		589
Debt				$ 589		589
Stated interest rate (in thousandths)				5.875%
Effective interest rate (in thousandths)				6.14%
Corporate bonds [Member] | 2023 senior notes [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Current debt				$ 0		0
Long-term debt				989		988
Debt				$ 989		988
Stated interest rate (in thousandths)				5.25%
Effective interest rate (in thousandths)				5.43%
Corporate bonds [Member] | 2024 senior notes [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Current debt				$ 0		0
Long-term debt				545		545
Debt				$ 545		545
Stated interest rate (in thousandths)				5.25%
Effective interest rate (in thousandths)				5.38%
Corporate bonds [Member] | 2025 senior notes [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Current debt				$ 0		0
Long-term debt				1,138		1,138
Debt				$ 1,138		1,138
Stated interest rate (in thousandths)				5.50%
Effective interest rate (in thousandths)				5.56%
Corporate bonds [Member] | 2026 senior notes [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Current debt				$ 0		0
Long-term debt				446		446
Debt				$ 446		446
Stated interest rate (in thousandths)				5.625%
Effective interest rate (in thousandths)				5.73%
Convertible Debt [Member]
Convertible Debt Issuances [Abstract]
Outstanding principal				$ 1,899
Underlying Shares (shares issuable upon conversion) | shares				119
Conversion value in excess of principal	[2]			$ 440
Conversion rights, minimum number of trading days (in days) | integer				20
Conversion rights, consecutive trading period (in days)				30 days
Conversion rights, threshold percentage of applicable conversion price (in hundredths)				130.00%
Convertible Debt [Member] | 2032C convertible senior notes [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Current debt	[4]			$ 0	[3]	0
Long-term debt	[4]			199	[3]	197
Debt	[4]			$ 199	[3]	197
Stated interest rate (in thousandths)				2.375%
Effective interest rate (in thousandths)				5.95%
Convertible Debt Issuances [Abstract]
Holder Put Date (Earliest)	[5]			May 31, 2019
Outstanding principal				$ 224
Underlying Shares (shares issuable upon conversion) | shares				23
Initial conversion, price per share | $ / shares				$ 9.63
Conversion price per share threshold (dollars per share) | $ / shares	[6]			$ 12.52
Conversion value in excess of principal	[2]			$ 138
Convertible Debt [Member] | 2032D convertible senior notes [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Current debt	[4]			0	[3]	0
Long-term debt	[4]			151	[3]	150
Debt	[4]			$ 151	[3]	150
Stated interest rate (in thousandths)				3.125%
Effective interest rate (in thousandths)				6.33%
Convertible Debt Issuances [Abstract]
Holder Put Date (Earliest)	[5]			May 31, 2021
Outstanding principal				$ 177
Underlying Shares (shares issuable upon conversion) | shares				18
Initial conversion, price per share | $ / shares				$ 9.98
Conversion price per share threshold (dollars per share) | $ / shares	[6]			$ 12.97
Conversion value in excess of principal	[2]			$ 100
Convertible Debt [Member] | 2033E convertible senior notes [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Current debt	[4]			165	[3]	217
Long-term debt	[4]			0	[3]	0
Debt	[4]			$ 165	[3]	217
Stated interest rate (in thousandths)				1.625%
Effective interest rate (in thousandths)				4.50%
Convertible Debt Issuances [Abstract]
Holder Put Date (Earliest)	[5]			Feb. 28, 2018
Outstanding principal				$ 176
Underlying Shares (shares issuable upon conversion) | shares				16
Initial conversion, price per share | $ / shares				$ 10.93
Conversion price per share threshold (dollars per share) | $ / shares	[6]			$ 14.21
Conversion value in excess of principal	[2]			$ 75
Convertible Debt [Member] | 2033F convertible senior note [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Current debt	[4]			266	[3]	264
Long-term debt	[4]			0	[3]	0
Debt	[4]			$ 266	[3]	264
Stated interest rate (in thousandths)				2.125%
Effective interest rate (in thousandths)				4.93%
Convertible Debt Issuances [Abstract]
Holder Put Date (Earliest)	[5]			Feb. 28, 2020
Outstanding principal				$ 297
Underlying Shares (shares issuable upon conversion) | shares				27
Initial conversion, price per share | $ / shares				$ 10.93
Conversion price per share threshold (dollars per share) | $ / shares	[6]			$ 14.21
Conversion value in excess of principal	[2]			$ 127
Convertible Debt [Member] | 2043G convertible senior notes [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Current debt	[4]			0		0
Long-term debt	[4]			647		644
Debt	[4]			$ 647		644
Stated interest rate (in thousandths)				3.00%
Effective interest rate (in thousandths)				6.76%
Convertible Debt Issuances [Abstract]
Holder Put Date (Earliest)	[5],[7]			Nov. 30, 2028
Outstanding principal	[7]			$ 1,025
Underlying Shares (shares issuable upon conversion) | shares				35
Initial conversion, price per share | $ / shares				$ 29.16
Conversion price per share threshold (dollars per share) | $ / shares	[6]			$ 37.91
Conversion value in excess of principal	[2]			$ 0
Debt Instrument Issued At A Discount Original Principal Amount	[7]			820
Debt Instrument, Scheduled Accreted Principal Amount	[7]			917
Debt Instrument, Face Amount	[7]			1,030
Other notes payable [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Current debt				100		34
Long-term debt				272		171
Debt				$ 372		$ 205
Weighted average stated interest rate (in thousandths)				2.462%
Weighted average effective interest rate (in thousandths)				2.65%
Other notes payable [Member] | Secured Debt 6 [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Debt				$ 213
Convertible Debt Issuances [Abstract]
Proceeds from Issuance of Other Long-term Debt		$ 174
Debt instrument, original term				3 years
Other notes payable [Member] | Secured Debt 6 [Member] | Libor [Member]
Convertible Debt Issuances [Abstract]
Debt Instrument Variable Reference Rate Period 1				3 months
Other notes payable [Member] | Secured Debt 6 [Member] | Libor [Member] | Maximum [Member]
Convertible Debt Issuances [Abstract]
Margin on variable rate financing (in hundredths)				2.20%
Loans Payable [Member]
Long-term Debt, by Maturity [Abstract]
Remainder of 2016				$ 329
2017				348
2018				507
2019				502
2020				695
2021 and thereafter				4,844
Unamortized amounts				(557)
Notes Payable				$ 6,668

[1] Weighted-average imputed rate of 3.8% and 3.7% as of December 3, 2015 and September 3, 2015, respectively.

[2] Based on our closing share price of $15.61 as of December 3, 2015.

[3] Since the closing price of our common stock for at least 20 trading days in the 30 trading day period ending on September 30, 2015 exceeded 130% of the conversion price per share, holders had the right to convert their notes at any time during the calendar quarter ended December 31, 2015. The closing price of our common stock also exceeded the thresholds for the calendar quarter ended December 31, 2015; therefore, these notes are convertible by the holders through March 31, 2016. The 2033 Notes are classified as current because the terms of these notes also require us to pay cash for the principal amount of any converted notes.

[4] We have either the obligation or the option to pay cash for the principal amount due upon conversion for all of our convertible notes. Since it is our current intent to settle in cash the principal amount of all of our convertible notes upon conversion, the dilutive effect of such notes on earnings per share is computed under the treasury stock method.

[5] The terms of our convertible notes give holders the right to require us to repurchase all or a portion of their notes at a date prior to the contractual maturity at a price equal to the principal amount thereof plus accrued interest.

[6] Holders have the right to convert all or a portion of their notes at a date prior to the contractual maturity if, during any calendar quarter, the closing price of our common stock for at least 20 trading days in the 30 consecutive trading days ending on the last trading day of the preceding calendar quarter is more than 130% of the conversion price. The closing price of our common stock exceeded the thresholds for the calendar quarter ended September 30, 2015 for our 2032 Notes and 2033 Notes; therefore, those notes were convertible by the holders through December 31, 2015. The closing price of our common stock also exceeded the thresholds for the calendar quarter ended December 31, 2015; therefore, these notes are convertible by the holders through March 31, 2016.

[7] The original principal amount of $820 million accretes up to $917 million in November 2028 and $1.03 billion at maturity in 2043.