Components of Accumulated Other Comprehensive Loss Net of Tax (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	$ (314)	$ (338)
Other comprehensive income (losses) before reclassifications	34	40
Amounts reclassified from accumulated other comprehensive loss	(11)	24
Net current-period other comprehensive income	23	64
Ending balance	(291)	(274)
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(255)	(244)
Other comprehensive income (losses) before reclassifications	20	45
Amounts reclassified from accumulated other comprehensive loss	(11)	(12)
Net current-period other comprehensive income	9	33
Ending balance	(246)	(211)
Accumulated Net Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance		(14)
Other comprehensive income (losses) before reclassifications		5
Amounts reclassified from accumulated other comprehensive loss		(2)
Net current-period other comprehensive income		3
Ending balance		(11)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance		(11)
Amounts reclassified from accumulated other comprehensive loss		11
Net current-period other comprehensive income		11
Accumulated Translation Adjustment and Other
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(59)	(69)
Other comprehensive income (losses) before reclassifications	14	(10)
Amounts reclassified from accumulated other comprehensive loss		27
Net current-period other comprehensive income	14	17
Ending balance	$ (45)	$ (52)