Equity - Additional Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions			3 Months Ended
		Sep. 30, 2018	Dec. 29, 2018	Sep. 29, 2018
Class of Stock [Line Items]
AOCI reclassifications to retained earnings, tax			$ (683)
AOCI reclassifications to retained earnings, before tax			(23)
AOCI reclassifications to retained earnings, net of tax	[1]		$ (706)
Remaining shares authorized for repurchase			158,000
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, authorized			100,000	100,000
Preferred stock, par value			$ 0.01	$ 0.01
Preferred stock, issued			0	0
Series B Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, authorized				40
Preferred stock, par value				$ 0.01
Investments
Class of Stock [Line Items]
AOCI reclassifications to retained earnings, tax			$ 9
AOCI reclassifications to retained earnings, before tax			(24)
AOCI reclassifications to retained earnings, net of tax	[1]		(15)
Cash Flow Hedges
Class of Stock [Line Items]
AOCI reclassifications to retained earnings, tax			(9)
AOCI reclassifications to retained earnings, before tax			1
AOCI reclassifications to retained earnings, net of tax	[1]		(8)
Unrecognized Pension and Postretirement Medical Expense
Class of Stock [Line Items]
AOCI reclassifications to retained earnings, tax			(667)
AOCI reclassifications to retained earnings, before tax			0
AOCI reclassifications to retained earnings, net of tax	[1]		(667)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Class of Stock [Line Items]
AOCI reclassifications to retained earnings, tax			(16)
AOCI reclassifications to retained earnings, before tax			0
AOCI reclassifications to retained earnings, net of tax	[1]		$ (16)
Accounting Standards Update 2018-02
Class of Stock [Line Items]
AOCI reclassifications to retained earnings, tax		$ 691
Accounting Standards Update 2016-01
Class of Stock [Line Items]
AOCI reclassifications to retained earnings, before tax		24
AOCI reclassifications to retained earnings, net of tax		$ 15

[1] On September 30, 2018, the Company adopted a FASB standard, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, and elected to reclassify $691 million from AOCI to retained earnings in the quarter ended December 29, 2018.In addition, on September 30, 2018, the Company adopted a FASB standard, Recognition and Measurement of Financial Assets and Liabilities, and reclassified $24 million ($15 million after tax) of market value adjustments on investments previously recorded in AOCI to retained earnings.