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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Accumulated Other Comprehensive Loss and Shareholders' Equity - Changes in Shareholders' Equity (Deficit) (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017	Jan. 01, 2016
(Increase) Decrease in Shareholders' Deficit [Roll Forward]
Balance at beginning of period			$ 3,731
Balance at beginning of period (in shares)			359.1
Balance at beginning of period (as adjusted)	$ 2,324		$ 2,324			$ 3,582
Net income	483	$ 485	1,491	$ 1,345
Other comprehensive loss	(65)	107	(288)	448
Dividends ($1.15 per share)			(404)
Share-based compensation plans			$ 44
Share-based compensation plans (in shares)			1.4
Purchase of treasury stock			$ (2,473)
Purchase of treasury stock (in shares)			(18.5)
Balance at end of period	$ 2,324		$ 2,324
Balance at end of period (in shares)	342.0		342.0
Cash dividends (in USD per share)			$ 1.15
Class A Common Stock
(Increase) Decrease in Shareholders' Deficit [Roll Forward]
Balance at beginning of period			$ 5
Balance at beginning of period (as adjusted)						5
Balance at end of period	$ 5		5
Additional Paid-in- Capital
(Increase) Decrease in Shareholders' Deficit [Roll Forward]
Balance at beginning of period			5,770
Balance at beginning of period (as adjusted)						5,770
Share-based compensation plans			3
Balance at end of period	5,773		5,773
Retained Earnings
(Increase) Decrease in Shareholders' Deficit [Roll Forward]
Balance at beginning of period			7,391
Balance at beginning of period (as adjusted)						7,242
Net income			1,491
Dividends ($1.15 per share)			(404)
Balance at end of period	8,705		8,705
Treasury Stock, at Cost
(Increase) Decrease in Shareholders' Deficit [Roll Forward]
Balance at beginning of period			(9,418)
Balance at beginning of period (as adjusted)						(9,418)
Share-based compensation plans			41
Purchase of treasury stock			(2,473)
Balance at end of period	(11,850)		(11,850)
Accumulated Other Comprehensive Loss
(Increase) Decrease in Shareholders' Deficit [Roll Forward]
Balance at beginning of period			(17)	(497)
Balance at beginning of period (as adjusted)						(17)
Other comprehensive loss			(288)
Balance at end of period	$ (309)	$ (49)	$ (309)	$ (49)
Adoption of ASU 2014-09
(Increase) Decrease in Shareholders' Deficit [Roll Forward]
Adoption of ASU						(149)
Adoption of ASU 2014-09 \| Retained Earnings
(Increase) Decrease in Shareholders' Deficit [Roll Forward]
Adoption of ASU						(149)	$ 264
Adoption of ASU 2014-09 \| Accumulated Other Comprehensive Loss
(Increase) Decrease in Shareholders' Deficit [Roll Forward]
Adoption of ASU						$ 0
Adoption of ASU 2016-01
(Increase) Decrease in Shareholders' Deficit [Roll Forward]
Adoption of ASU					$ 0
Adoption of ASU 2016-01 \| Retained Earnings
(Increase) Decrease in Shareholders' Deficit [Roll Forward]
Adoption of ASU					4
Adoption of ASU 2016-01 \| Accumulated Other Comprehensive Loss
(Increase) Decrease in Shareholders' Deficit [Roll Forward]
Adoption of ASU					(4)
Adoption of ASU 2016-16
(Increase) Decrease in Shareholders' Deficit [Roll Forward]
Adoption of ASU					372
Adoption of ASU 2016-16 \| Retained Earnings
(Increase) Decrease in Shareholders' Deficit [Roll Forward]
Adoption of ASU					$ 372