Employee Benefit Plans - Restricted Stock Units (Details) - $ / shares shares in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2020
TSR PSUs \| Chief Executive Officer \| Performance Period One
Stock-based Compensation Arrangement by Stock-based Payment Award
Performance period	2 years
Vesting percentage	50.00%
TSR PSUs \| Chief Executive Officer \| Performance Period Two
Stock-based Compensation Arrangement by Stock-based Payment Award
Performance period	3 years
Vesting percentage	50.00%
Restricted Stock Units (RSUs)
Units
Outstanding, beginning of period (in shares)		28
Awarded (in shares)		14
Vested (in shares)		(6)
Forfeited (in shares)		(6)
Outstanding, end of period (in shares)	30	30
Weighted average grant date fair value (in usd per share)		$ 30.56

Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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-Name Accounting Standards Codification
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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Percentage of vesting of award under share-based payment arrangement.

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