Business Segments - Segment Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Assets	$ 16,506	$ 17,185
Operating Segments
Segment Reporting Information [Line Items]
Assets	14,216	15,041
Operating Segments | Americas
Segment Reporting Information [Line Items]
Assets	6,666	7,606
Operating Segments | Europe, Middle East and Africa
Segment Reporting Information [Line Items]
Assets	4,825	4,724
Operating Segments | Asia Pacific
Segment Reporting Information [Line Items]
Assets	2,725	2,711
Corporate
Segment Reporting Information [Line Items]
Assets	$ 2,290	$ 2,144