Income Taxes - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) country	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Total Gross Unrecognized Tax Benefits
Tax Cuts and Jobs Act, tax expense (benefit)	$ (25)
Operating loss carryforwards	1,591	$ 1,500
Valuation allowances	1,835	1,591
Deferred tax assets, operating loss carryforwards, foreign	290
Deferred tax liability not provided for temporary difference	6,700
Tax liabilities for gross unrecognized tax benefits	451	$ 472	$ 395
Interest accrued on income taxes for unrecognized tax benefits	93
Penalties accrued on income taxes for unrecognized tax benefits	29
Uncertain tax positions	573
Unrecognized tax benefits that would impact effective tax rate	515
Deferred tax asset that we did not prevail on all uncertain tax position	58
Deferred tax asset that we did not prevail on all uncertain tax position, foreign taxing jurisdiction	21
Deferred tax asset that we did not prevail on all uncertain tax position, increased valuation allowances	37
Uncertain tax positions, liabilities	$ 67
Number of countries in which entity operates (more than) | country	120
Foreign Net Operating Loss
Total Gross Unrecognized Tax Benefits
Valuation allowances	$ 1,257
US And Foreign Tax Credit Carryforward
Total Gross Unrecognized Tax Benefits
Valuation allowances	366
Other United States Net Operating Loss Tax Credit Carryforward
Total Gross Unrecognized Tax Benefits
Valuation allowances	46
Other US And Foreign Deferred Tax Assets
Total Gross Unrecognized Tax Benefits
Valuation allowances	166
Five year carryforward
Total Gross Unrecognized Tax Benefits
Operating loss carryforwards	$ 331
Expiration of operation loss carryforwards over the next 5 years	5 years
Six to twenty year carryforward
Total Gross Unrecognized Tax Benefits
Operating loss carryforwards	$ 326
Minimum | Six to twenty year carryforward
Total Gross Unrecognized Tax Benefits
Expiration of operation loss carryforwards over the next six to 20 years	6 years
Maximum | Six to twenty year carryforward
Total Gross Unrecognized Tax Benefits
Expiration of operation loss carryforwards over the next six to 20 years	20 years
Indefinite Foreign Tax
Total Gross Unrecognized Tax Benefits
Deferred tax assets, tax credit carryforwards, foreign	$ 366
Other Tax
Total Gross Unrecognized Tax Benefits
Deferred tax assets, tax credit carryforwards	$ 32