Fair Value Measurements Fair Value, Assets Measured on Nonrecurring Basis Using Unobservable Inputs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Asset Impairment Charges	$ 443	$ 93	$ 113
Fair Value Measurements Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Asset Impairment Charges	443	93
Assets, Fair Value Disclosure	183	145
Property, Plant and Equipment [Member] | Fair Value Measurements Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Asset Impairment Charges	4	4
Property, Plant and Equipment [Member] | Fair Value Measurements Nonrecurring [Member] | Level 3 [Member] | Valuation, Income Approach [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	41	44
Other assets and Acquired intangible assets [Member] | Fair Value Measurements Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Asset Impairment Charges	310
Other assets and Acquired intangible assets [Member] | Fair Value Measurements Nonrecurring [Member] | Level 3 [Member] | Valuation, Income Approach [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	4
Operating Lease Equipment And Assets Held For Sale Or Re-Lease [Member] | Fair Value Measurements Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Asset Impairment Charges	20	39
Operating Lease Equipment And Assets Held For Sale Or Re-Lease [Member] | Fair Value Measurements Nonrecurring [Member] | Level 3 [Member] | Valuation, Market Approach [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	111	101
Investments [Member] | Fair Value Measurements Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Asset Impairment Charges	109	50
Investments [Member] | Fair Value Measurements Nonrecurring [Member] | Level 3 [Member] | Valuation, Income Approach [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	$ 27