Investment In Unconsolidated Affiliates Carrying Value of Unconsolidated Affiliates (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Investment in unconsolidated affiliates, carrying value	$ 2,224	$ 2,214
HPC [Member]
Investment in unconsolidated affiliates, carrying value	637	650
MEP
Investment in unconsolidated affiliates, carrying value	564	581
Lone Star
Investment in unconsolidated affiliates, carrying value	987	948
Ranch JV
Investment in unconsolidated affiliates, carrying value	36	35
Grey Ranch JV [Member]
Investment in unconsolidated affiliates, carrying value	$ 0	$ 0