Provision (Benefit) for Income Taxes Reconciliations to Recorded Tax Provision (Benefit) Table (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Effective Income Tax Rate Reconciliation [Abstract]
Provision (benefit) at statutory rate	$ (600)	$ 1,255	$ 378
Increases (decreases) in taxes resulting from:
Impact of nontaxable noncontrolling interests	263	(75)	(78)
State income taxes (net of federal benefit)	(21)	82	26
Foreign operations – net	8	(11)	(32)
Taxes on undistributed earnings of foreign subsidiaries – net	0	(37)	99
Translation adjustment of certain unrecognized tax benefits	(71)	0	0
Other – net	22	35	8
Provision (benefit) for income taxes	$ (399)	$ 1,249	$ 401