10-Q Capital Stock (Summary of Cash Dividend Activity) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended											9 Months Ended		12 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Banking Regulation, Total Capital [Abstract]
Declaration date	Jul. 18, 2023	Apr. 18, 2023	Jan. 24, 2023	Oct. 18, 2022	Jul. 19, 2022	Apr. 19, 2022	Jan. 25, 2022	Oct. 19, 2021	Jul. 20, 2021	Apr. 20, 2021	Jan. 26, 2021
Record date	Sep. 08, 2023	Jun. 09, 2023	Mar. 10, 2023	Dec. 05, 2022	Sep. 09, 2022	Jun. 10, 2022	Mar. 10, 2022	Dec. 03, 2021	Sep. 10, 2021	Jun. 10, 2021	Mar. 10, 2021
Payment date	Sep. 22, 2023	Jun. 23, 2023	Mar. 24, 2023	Dec. 21, 2022	Sep. 23, 2022	Jun. 24, 2022	Mar. 25, 2022	Dec. 21, 2021	Sep. 24, 2021	Jun. 25, 2021	Mar. 25, 2021
Cash dividends per share	$ 1.48	$ 1.48	$ 1.48	$ 1.28	$ 1.28	$ 1.28	$ 1.28	$ 1.13	$ 1.13	$ 1.13	$ 1.13
Total payment	$ 348	$ 350	$ 351	$ 305	$ 306	$ 309	$ 309	$ 273	$ 276	$ 278	$ 277	$ 1,049	$ 924	$ 1,229	$ 1,104	$ 954