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Goodwill (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
Goodwill (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Goodwill [Line Items]
Goodwill	$ 458	$ 458		$ 458	$ 458	$ 458
Accumulated impairment loss	1,819			1,819		$ 1,819
Goodwill impairment charge	$ 0	$ 0		$ 0	$ 784
Wealth and Personal Banking [Member]
Goodwill [Line Items]
Goodwill impairment charge			$ 784