New Accounting Standards (Statement of Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Expenses Excluding Interest
Compensation and benefits	$ 770	$ 701
Taxes on income	219	279
Net income	783	$ 564	[1]
Balances Without Adoption of ASC 606 [Member] | ASU 2014-09 [Member]
Expenses Excluding Interest
Compensation and benefits	781
Taxes on income	216
Net income	775
Effect of Change Higher/(Lower) [Member] | ASU 2014-09 [Member]
Expenses Excluding Interest
Compensation and benefits	(11)
Taxes on income	3
Net income	$ 8

[1] Adjusted for the retrospective adoption of ASU 2016-18. See Note 2.