Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Consolidated Balance Sheets
Payables due to affiliates	$ 7	$ 14
Deferred revenue to affiliates	$ 38	$ 32
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, authorized shares	1,250,000	1,250,000
Common stock, issued shares	1,160,779	1,164,848
Common stock, outstanding shares	1,160,779	1,164,848