Summary of Significant Accounting Policies Update (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 29, 2019	Jan. 01, 2019
Summary of Significant Accounting Policies Update
Operating right-of-use assets	$ 298
Operating lease liabilities	$ 300
Lease, Practical Expedient, Use of Hindsight [true false]	true
ASU 2016-02
Summary of Significant Accounting Policies Update
Operating right-of-use assets		$ 307
Operating lease liabilities		$ 307