Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accounts Receivable, Allowance for Credit Loss, Current	$ 13	$ 20
Other Current Assets, Allowance	0	0
Finite-Lived Intangible Assets, Accumulated Amortization	330	307
Loans and Leases Receivable, Allowance	0	0
Other Noncurrent Assets, Allowance	21	0
Non Recourse Debt Current	1,430	1,868
Non Recourse Debt Non Current	$ 15,005	$ 14,914
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,200,000,000	1,200,000,000
Common stock, shares issued (in shares)	818,398,654	817,843,916
Common stock, shares outstanding (in shares)	665,370,128	663,952,656
Treasury stock, shares (in shares)	153,028,526	153,891,260
Consolidated Variable Interest Entities [Member]
Non Recourse Debt Current	$ 336	$ 337
Non Recourse Debt Non Current	$ 3,918	$ 3,872