Supplemental Financial Information - Accumulated other comprehensive income (loss) (Details) $ in Millions	9 Months Ended
	Sep. 27, 2020 USD ($)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	$ 9,655
Other comprehensive income (loss) before reclassifications	12
Amounts reclassified out of accumulated other comprehensive income (loss)	3
Other comprehensive income (loss)	0
Other comprehensive income (loss)	15
Balance	9,073
Currency  translation differences
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	203
Other comprehensive income (loss) before reclassifications	14
Amounts reclassified out of accumulated other comprehensive income (loss)	0
Other comprehensive income (loss)	0
Other comprehensive income (loss)	14
Balance	217
Change in fair  value cash flow hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	2
Other comprehensive income (loss) before reclassifications	3
Amounts reclassified out of accumulated other comprehensive income (loss)	3
Other comprehensive income (loss)	(1)
Other comprehensive income (loss)	5
Balance	7
Net actuarial gain/(losses)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(130)
Other comprehensive income (loss) before reclassifications	(5)
Amounts reclassified out of accumulated other comprehensive income (loss)	0
Other comprehensive income (loss)	1
Other comprehensive income (loss)	(4)
Balance	(134)
Accumulated other comprehensive income (loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	75
Balance	$ 90