Contingencies and Commitments - Additional Information - 1 (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2009
Loss Contingencies [Line Items]
Number of cleanup locations		More than 100
Remediation reserve balance	$ 574	$ 574	$ 543
Remediation reserve balance, classified as a current liability	53	53	70
Payments related to remediation expenses applied against the reserve	10	16
Increase (Decrease) in reserves due to effects of foreign currency translation	1	$ (6)
Actual remediation fieldwork period		4 years
Guarantee debt service expiration year		2019
Minimum [Member]
Loss Contingencies [Line Items]
Planning and design phase period		2 years
Majority of the project funding period		2016
Maximum [Member]
Loss Contingencies [Line Items]
Planning and design phase period		3 years
Majority of the project funding period		2020
Recurring Costs of Managing Hazardous Substances and Environmental Programs [Member]
Loss Contingencies [Line Items]
Percentage of cost of goods sold		2.00%
Sherwin, TX site [Member]
Loss Contingencies [Line Items]
Remediation reserve balance	32	$ 32	32
Expected portion of funding through 2019	16	16
Massena West, NY [Member]
Loss Contingencies [Line Items]
Remediation reserve balance	237	237	239
East St. Louis, IL Site [Member]
Loss Contingencies [Line Items]
Remediation reserve balance	14	14	15
Grasse River [Member]
Loss Contingencies [Line Items]
Increase in remediation reserve	45	53
Pocos De Caldas Smelter and the Anglesea Power Station [Member]
Loss Contingencies [Line Items]
Remediation reserve adjustment	29
Mosjoen [Member]
Loss Contingencies [Line Items]
Increase in remediation reserve	11			$ 20
Other Sites [Member]
Loss Contingencies [Line Items]
Remediation reserve adjustment	$ 5	6
Portovesme [Member]
Loss Contingencies [Line Items]
Increase in remediation reserve			$ 3		$ 3
Remediation reserve adjustment		$ 7