Correction of Prior Period Amounts (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Other assets	$ 8,496	$ 6,537
Other liabilities	2,520	2,251
Retained earnings	10,101	9,116	$ 8,473	$ 7,681
Noncontrolling interests	$ 153	215	264	287
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Other assets		6,527
Other liabilities		2,257
Retained earnings		9,134	8,491	7,699
Noncontrolling interests		181	230	253
Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Other assets		10
Other liabilities		(6)
Retained earnings		(18)	(18)	(18)
Noncontrolling interests		$ 34	$ 34	$ 34