Information Relating to the Consolidated Statement of Cash Flows - Narrative (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Equity, Class of Treasury Stock [Line Items]
Purchases (in shares)	10,302,969	6,255,290	23,342,737	6,262,987
Purchases of treasury shares	$ 1,250	$ 750	$ 2,789	$ 751
Dividends paid (in dollars per share)	$ 1.19	$ 1.12	$ 3.57	$ 3.36
Share Repurchase Programs
Equity, Class of Treasury Stock [Line Items]
Purchases (in shares)			23,300	6,300
Purchases of treasury shares			$ 2,800	$ 750