Restructuring (Narrative) (Detail) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) Employee	Jun. 30, 2014 USD ($)	Dec. 31, 2015 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 3	$ 1	$ 4	$ 8
Restructuring and Related Cost, Expected Cost					$ 20
2014 T15 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Number of Positions Eliminated | Employee			250
Restructuring and Related Cost, Number of Positions Eliminated | Employee			100
Restructuring Charges			$ 4
Restructuring and Related Cost, Expected Cost					$ 5