Accumulated Other Comprehensive Loss - Changes (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Jan. 01, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
AOCI roll forward
Beginning balance	$ 6,042			$ 6,042
Other comprehensive income (loss), net of tax		$ 33	$ 47	(19)	$ 94
Ending balance		6,241		6,241
Accumulated Other Comprehensive Loss [Member]
AOCI roll forward
Beginning balance	8			8
Other comprehensive income (loss) before reclassifications, net of tax				(25)
Amounts reclassified from accumulated other comprehensive (income) loss, net of tax				6
Other comprehensive income (loss), net of tax				(19)
Ending balance		(16)		(16)
Derivative Instruments [Member]
AOCI roll forward
Beginning balance	(33)			(33)
Amounts reclassified from accumulated other comprehensive (income) loss, net of tax				6
Other comprehensive income (loss), net of tax				6
Ending balance		(34)		(34)
Available for sale Securities [Member]
AOCI roll forward
Beginning balance	15			15
Other comprehensive income (loss) before reclassifications, net of tax				8
Other comprehensive income (loss), net of tax				8
Ending balance		26		26
Foreign Currency Translation Adjustments [Member]
AOCI roll forward
Beginning balance	29			29
Other comprehensive income (loss) before reclassifications, net of tax				(33)
Other comprehensive income (loss), net of tax				(33)
Ending balance		(4)		(4)
Post - Retirement Benefit Obligation [Member]
AOCI roll forward
Beginning balance	(3)			(3)
Ending balance		$ (4)		(4)
Accounting Standards Update 2018-02 [Member]
AOCI roll forward
Adoption of new accounting standard	$ (5)
Accounting Standards Update 2018-02 [Member] | Accumulated Other Comprehensive Loss [Member]
AOCI roll forward
Adoption of new accounting standard				(5)
Accounting Standards Update 2018-02 [Member] | Derivative Instruments [Member]
AOCI roll forward
Adoption of new accounting standard				(7)
Accounting Standards Update 2018-02 [Member] | Available for sale Securities [Member]
AOCI roll forward
Adoption of new accounting standard				3
Accounting Standards Update 2018-02 [Member] | Post - Retirement Benefit Obligation [Member]
AOCI roll forward
Adoption of new accounting standard				$ (1)