Fair Value Measurements Fair Value, Assets Measured on Nonrecurring Basis Using Unobservable Inputs (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring fair value losses	$ (106)	$ (63)
Fair Value Measurements Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring fair value losses	(106)	(63)
Fair Value Measurements Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	105	45
Operating Lease Equipment And Assets Held For Sale Or Re-Lease [Member] | Fair Value Measurements Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring fair value losses	(1)	(16)
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 Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	10	45
Property, Plant and Equipment [Member] | Fair Value Measurements Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring fair value losses	(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 Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	41
Investments [Member] | Fair Value Measurements Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring fair value losses	(84)	$ (47)
Investments [Member] | Fair Value Measurements Nonrecurring [Member] | Level 3 [Member] | Valuation, Income Approach [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	51
Other assets and Acquired intangible assets [Member] | Fair Value Measurements Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring fair value losses	(17)
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 Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	$ 3