Intangibles Assets, Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Total annual intangible asset amortization expense
Intangible assets (net of accumulated amortization)	$ 1,732		$ 1,732		$ 1,883
Amortization expense	45	$ 45	135	$ 134
Customer-Related Intangible Assets [Member]
Total annual intangible asset amortization expense
Intangible assets (net of accumulated amortization)	1,642		1,642		1,785
Accumulated amortization	830		830		729
Computer Software, Intangible Asset [Member]
Total annual intangible asset amortization expense
Intangible assets (net of accumulated amortization)	66		66		69
Accumulated amortization	186		186		196
Other Intangible Assets [Member]
Total annual intangible asset amortization expense
Intangible assets (net of accumulated amortization)	24		24		29
Accumulated amortization	$ 96		$ 96		$ 124