Significant Accounting Policies - Impact of Adoption of ASC 842 to Consolidated Balance Sheet (Details) - USD ($) $ in Millions	Sep. 28, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses and other current assets	$ 66	$ 53	$ 54
Right-of-use assets	117	110
Accrued liabilities	314	350	322
Long-term lease liabilities	105	103
Other long-term liabilities	$ 86	67	$ 89
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses and other current assets		(1)
Right-of-use assets		110
Accrued liabilities		28
Long-term lease liabilities		103
Other long-term liabilities		$ (22)