Capital Stock - Dividends Common Stock (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Equity [Abstract]
Fixed (in dollars per share)	$ 0.20	$ 0.20	$ 0.20	$ 0.15	$ 0.15	$ 0.15	$ 0.60	$ 0.45
Variable (in dollars per share)	0	0	0.37	0.50	0.45	0.41	0.37	1.36
Total (in dollars per share)	$ 0.20	$ 0.20	$ 0.57	$ 0.65	$ 0.60	$ 0.56	$ 0.97	$ 1.81
Total dividends	$ 153	$ 153	$ 438	$ 519	$ 484	$ 455	$ 744	$ 1,458