Long-Term Incentive Compensation Plans (Deferred Cash-based Compensation Plans) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Deferred Cash-based Compensation Plans
Compensation expense	$ 2,250		$ 1,941		$ 1,236
Deferred cash-based compensation expense recorded in discontinued operations	7		7		9
Deferred Cash-based Awards
Deferred Cash-based Compensation Plans
Compensation expense	1,815	[1]	1,809	[1]	771	[1]
Unrecognized compensation cost related to unvested cash-based awards	782
Unrecognized compensation cost will be recognized in 2013, absent actual cancellations and any future return on referenced investments	540
Unrecognized compensation cost will be recognized in 2014, absent actual cancellations and any future return on referenced investments	104
Unrecognized compensation cost will be recognized thereafter, absent actual cancellations and any future return on referenced investments	138
Deferred Cash-based Awards | Employee Who Satisfied Retirement Eligible Requirements under Award Terms that Do Not Contain Service Period
Deferred Cash-based Compensation Plans
Compensation expense	93		113		80
Return on Referenced Investments
Deferred Cash-based Compensation Plans
Compensation expense	$ 435		$ 132		$ 465

[1] Amounts for 2012, 2011 and 2010 include $93 million, $113 million and $80 million, respectively, related to deferred awards that were granted in 2013, 2012 and 2011, respectively, to employees who satisfied retirement-eligible requirements under the award terms that do not contain a service period.