Intangibles Assets, Net (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Total annual intangible asset amortization expense
Intangible assets (net of accumulated amortization)	$ 1,813		$ 1,883
Amortization expense	45	$ 45
Customer-Related Intangible Assets [Member]
Total annual intangible asset amortization expense
Intangible assets (net of accumulated amortization)	1,721		1,785
Accumulated amortization	756		729
Computer Software, Intangible Asset [Member]
Total annual intangible asset amortization expense
Intangible assets (net of accumulated amortization)	66		69
Accumulated amortization	201		196
Other Intangible Assets [Member]
Total annual intangible asset amortization expense
Intangible assets (net of accumulated amortization)	26		29
Accumulated amortization	$ 93		$ 124