Retirement Plans - Amounts recognized in the balance sheets (Details) - USD ($) $ in Millions	Dec. 31, 2016	Jan. 02, 2016
Pension Benefits
Amounts recognized in our balance sheets
Non-current assets	$ 63	$ 73
Current liabilities	(26)	(26)
Non-current liabilities	(1,154)	(855)
Recognized in Accumulated other comprehensive loss, pre-tax :
Net loss	2,187	1,915
Prior service cost (credit)	78	92
Postretirement Benefits Other Than Pensions
Amounts recognized in our balance sheets
Current liabilities	(35)	(40)
Non-current liabilities	(282)	(324)
Recognized in Accumulated other comprehensive loss, pre-tax :
Net loss	(8)	9
Prior service cost (credit)	$ (40)	$ (50)

No definition available.

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- Definition

The pretax net amount of gains and losses that are not yet recognized as a component of net periodic benefit cost, and that are recognized as increases or decreases in other comprehensive income as they arise. Gains and losses are due to changes in the value of either the benefit obligation or the plan assets resulting from experience different from that assumed or from a change in an actuarial assumption, or the consequence of a decision to temporarily deviate from the substantive plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
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- Definition

Amount related to the pretax cost of benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation, which has not yet been recognized as components of net periodic benefit cost.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Prior Service Cost
-URI http://asc.fasb.org/extlink&oid=49177896

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- References

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- Definition

The amount for overfunded plans recognized in the balance sheet as a noncurrent asset associated with a defined benefit pension plan or other postretirement defined benefit plan.

+ References

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-Publisher FASB
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- Definition

For a classified balance sheet, the amount recognized in balance sheet as a current liability associated with an underfunded defined benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Current Liabilities
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- Definition

This represents the noncurrent liability for underfunded plans recognized in the balance sheet that is associated with the defined benefit pension plans and other postretirement defined benefit plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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