Consolidated Statement of Income (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Provision for credit losses, debt securities	$ 172	$ 0	[1]

[1]
(1) Prior to our adoption of Accounting Standards Update (ASU) 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (CECL), on January 1, 2020, provision for credit losses from debt securities was not applicable and is therefore presented as $0 for the prior period. For more information, see Note 1 (Summary of Significant Accounting Policies) to Financial Statements in this Report.