Identifiable Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 971	$ 504
Accumulated Amortization	179	183
Customer Relationships And Lists
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	615	227
Accumulated Amortization	85	82
Noncompete Agreements
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	68	72
Accumulated Amortization	23	19
Tradenames, Patents And Trademarks
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	149	51
Accumulated Amortization	22	21
Land And Water Rights
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	69	60
Accumulated Amortization	5	3
Fuel And Power Agreements
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	29	30
Accumulated Amortization	18	16
Software
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	25	37
Accumulated Amortization	23	29
Other Intangible Assets
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	16	27
Accumulated Amortization	$ 3	$ 13