Consolidated Statement of Cash Flows - Restricted Cash	6 Months Ended
Consolidated Statement of Cash Flows - Restricted Cash	Jun. 30, 2021
Consolidated Statement of Cash Flows [Abstract]
Consolidated Statement of Cash Flows - Restricted Cash	Restricted cash of $ 95 million and $ 253 million are included in the "Prepaid expenses and other current assets" and "Other assets" lines, respectively, of our Consolidated Balance Sheet as of June 30, 2021. Restricted cash of $ 94 million and $ 230 million are included in the "Prepaid expenses and other current assets" and "Other assets" lines, respectively, of our Consolidated Balance Sheet as of December 31, 2020. See Notes to Consolidated Financial Statements.