Business Developments Consumer Home Loan Portfolio Sale (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Gain (Loss) on Securities [Line Items]
Net transfers from loans held for investment to loans held for sale	$ 855	$ 674	$ 552
Benefit for credit losses	(5,856)	(7,551)	(6,459)
Other
Gain (Loss) on Securities [Line Items]
Benefit for credit losses	49	$ (4)	$ 5
Consumer Portfolio Segment \| Home loan \| Other
Gain (Loss) on Securities [Line Items]
Gain (Loss) on Sale of Mortgage Loans	499
Benefit for credit losses	$ 46

The gains (losses) included in earnings that represent the difference between the sale price and the carrying value of loans made to finance real estate acquisitions. This element refers to the gain (loss) and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

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Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

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Value of loans and leases held in the entity's portfolio transferred to loans and leases held-for-sale in noncash transactions.

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