Income Taxes - Components of Net Deferred Tax Liability (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred Tax Assets:
Net operating loss and other loss carryforwards	$ 3,194	$ 2,609
Nondeductible accruals and other	3,246	3,253
Less: Valuation allowance	2,907	2,312	$ 1,906	$ 632
Total deferred tax assets, net of valuation allowance	3,533	3,550
Deferred Tax Liabilities:
Differences between book and tax basis of property and equipment and intangible assets	30,584	29,829
Differences between book and tax basis of investments	526	405
Differences between book and tax basis of long-term debt	1,788	680
Differences between book and tax basis of foreign subsidiaries and undistributed foreign earnings	394	468
Total deferred tax liabilities	33,292	31,382
Net deferred tax liability	$ 29,759	$ 27,832