Redeemable Preferred Stock and Warrants (Details) - USD ($) $ / shares in Units, $ in Millions			6 Months Ended
	Jul. 02, 2015	Jun. 07, 2013	Jun. 28, 2015	Jun. 07, 2021	Jun. 07, 2020	Jun. 07, 2019	Jun. 07, 2018	Jun. 07, 2017	Jun. 07, 2016	Dec. 28, 2014
Preferred Units [Line Items]
Preferred stock, value, outstanding		$ 7,633
Warrants		$ 367	$ 0							$ 367
Preferred Stock
Preferred Units [Line Items]
Preferred stock, shares authorized			80,000
Preferred stock, shares issued			80,000
Dividends payable, annual, percent			9.00%
Preferred stock, redeemable, nonredeemable period		3 years
Temporary equity, accretion to redemption value, adjustment			$ (687)
Scenario, Forecast | Preferred Stock
Preferred Units [Line Items]
Preferred stock, redemption price per share				$ 108,000	$ 108,000	$ 107,000	$ 106,000	$ 105,000	$ 104,000
Berkshire Hathaway
Preferred Units [Line Items]
Dividends payable, annual, percent			9.00%
Business Acquisition, aggregate purchase price		$ 8,000
Preferred stock, value, outstanding			$ 8,000
Berkshire Hathaway | Preferred Stock
Preferred Units [Line Items]
Preferred stock, shares authorized		80,000
Preferred stock, shares issued		80,000
Dividends payable, annual, percent		9.00%
Warrant, exercise price per share		$ 0.01
Preferred stock, liquidation preference per share		$ 100,000
Berkshire Hathaway | Warrants
Preferred Units [Line Items]
Noncash or part noncash acquisition, equity consideration, warrants issued		46,000,000
Subsequent Event | Berkshire Hathaway | Warrants
Preferred Units [Line Items]
Noncash or part noncash acquisition, equity consideration, warrants issued	20,000,000