Goodwill And Identifiable Intangible Assets (Identifiable Intangible Assets Reported in the Balance Sheet) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Finite-Lived and Indefinite-Lived Intangible [Line Items]
Gross Carrying Amount	$ 2,156	$ 2,092
Accumulated Amortization	1,386	1,279
Total intangible assets subject to amortization, net	770	813
Total identifiable intangible assets	1,736	1,781
Retail trade name (not subject to amortization) [Member]
Finite-Lived and Indefinite-Lived Intangible [Line Items]
Gross Carrying Amount, Unamortized Intangibles	955	955
Mineral interests (not currently subject to amortization) [Member]
Finite-Lived and Indefinite-Lived Intangible [Line Items]
Gross Carrying Amount, Unamortized Intangibles	11	13
Retail customer relationship [Member]
Finite-Lived and Indefinite-Lived Intangible [Line Items]
Gross Carrying Amount	463	463
Accumulated Amortization	396	378
Total intangible assets subject to amortization, net	67	85
Favorable purchase and sales contracts [Member]
Finite-Lived and Indefinite-Lived Intangible [Line Items]
Gross Carrying Amount	551	552
Accumulated Amortization	333	314
Total intangible assets subject to amortization, net	218	238
Software and other computer-related assets [Member]
Finite-Lived and Indefinite-Lived Intangible [Line Items]
Gross Carrying Amount	348	320
Accumulated Amortization	145	112
Total intangible assets subject to amortization, net	203	208
Environmental allowances and credits [Member]
Finite-Lived and Indefinite-Lived Intangible [Line Items]
Gross Carrying Amount	598	594
Accumulated Amortization	407	393
Total intangible assets subject to amortization, net	191	201
Mining development costs [Member]
Finite-Lived and Indefinite-Lived Intangible [Line Items]
Gross Carrying Amount	196	163
Accumulated Amortization	105	82
Total intangible assets subject to amortization, net	$ 91	$ 81