Consolidated Statements of Shareholders' Equity (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Stockholders' Equity [Abstract]
Common treasury shares (in shares)	45,813,109	46,292,384	38,308,825	26,866,893
Tax on foreign currency translation	$ 4	$ (10)	$ 39
Tax on amortization of prior service cost and unrecognized gains and losses included in total benefit cost	33	34	40
Tax on increase in net actuarial losses	(42)	1	(37)
Tax on immediate recognition of prior service cost and unrecognized gains and losses due to curtailments, settlements, and divestitures	2	5	14
Tax on prior service cost from plan amendments	1	(3)	(2)
Tax effect of deferred derivative gains	0	3	(8)
Tax effect of reclassification adjustment for amounts recognized in income	$ 0	$ 0	$ 1
Cash dividends declared per common share (in dollars per share)	$ 0.64	$ 0.58	$ 0.44