Leases - Effect of Adopting New Lease Standard (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, net	$ 14,976		$ 16,045
Deferred charges and other assets	910		383
Accrued expenses and other current liabilities	1,323		1,217
Deferred credits and other liabilities	$ 1,968		849
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, net		$ 15,949	16,045
Deferred charges and other assets		863	383
Accrued expenses and other current liabilities		1,250	1,217
Financing obligations		9,961	10,057
Deferred credits and other liabilities		1,296	$ 849
Effect of Adoption | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, net		(96)
Deferred charges and other assets		480
Accrued expenses and other current liabilities		33
Financing obligations		(96)
Deferred credits and other liabilities		$ 447