Non-U.S. Activities - Schedule Of Results From Non-U.S. Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total revenue	$ 11,170	$ 10,207	$ 10,360
Income before income taxes	2,899	2,120	2,298
Non-U.S.
Segment Reporting Information [Line Items]
Total revenue	4,734	4,419	4,428
Income before income taxes	1,230	1,047	1,193
U.S.
Segment Reporting Information [Line Items]
Total revenue	6,436	5,788	5,932
Income before income taxes	$ 1,669	$ 1,073	$ 1,105