Summary of Significant Accounting Policies (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jul. 01, 2018 USD ($)	Jul. 01, 2018 USD ($) Segment	Jan. 01, 2018 USD ($)
New Accounting Pronouncements
Number of operating segments | Segment		5
Length of fiscal quarters, weeks		91 days
Operating Earnings | Accounting Standards Update 2017-07
New Accounting Pronouncements
New accounting pronouncement, effect of change in operating results	$ 11	$ 22
Other Income | Accounting Standards Update 2017-07
New Accounting Pronouncements
New accounting pronouncement, effect of change in operating results	$ (11)	$ (22)
Retained Earnings | Accounting Standards Update 2016-01
New Accounting Pronouncements
Cumulative effect of new accounting pronouncement in period of adoption			$ 24
Retained Earnings | Accounting Standards Update 2018-02
New Accounting Pronouncements
Cumulative effect of new accounting pronouncement in period of adoption			614
Accumulated Other Comprehensive Loss | Accounting Standards Update 2016-01
New Accounting Pronouncements
Cumulative effect of new accounting pronouncement in period of adoption			(24)
Accumulated Other Comprehensive Loss | Accounting Standards Update 2018-02
New Accounting Pronouncements
Cumulative effect of new accounting pronouncement in period of adoption			$ (614)