Investment In Unconsolidated Affiliates Carrying Value of Unconsolidated Affiliates (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Equity Method Investments	$ 2,178	$ 2,097
HPC [Member]
Equity Method Investments	439	442
MEP {Member]
Equity Method Investments	541	548
Lone Star {Member]
Equity Method Investments	1,097	1,070
Ranch JV {Member]
Equity Method Investments	38	36
Aqua - PVR [Member]
Equity Method Investments	51	0
Coal Handling [Member]
Equity Method Investments	12	0
Grey Ranch JV [Member]
Equity Method Investments	$ 0	$ 1