Assets And Liabilities Measured At Fair Value Realized Unrealized Gain Loss (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Realized and unrealized gains on financial instruments, net	$ (18)	$ (59)
Non-Strategic Securities [Member]
Realized and unrealized gains on financial instruments, net	140	97
Exchangeable Senior Debentures [Member]
Realized and unrealized gains on financial instruments, net	(182)	(187)
Other [Member]
Realized and unrealized gains on financial instruments, net	$ 24	$ 31