Variable Interest Entities (VIEs) (Details) - MWCC LLC [Member] $ in Millions	9 Months Ended
Sep. 30, 2018 USD ($)
Variable Interest Entity [Line Items]
Book value of equity method investment	$ 132
MWCC Board Members	ten
MWCC LLC [Member]
Variable Interest Entity [Line Items]
Ownership percentage in equity investment	10.00%
Term loan backed by a letter of credit	$ 154
Letter of Credit [Member] \| MWCC LLC [Member]
Variable Interest Entity [Line Items]
Debt at face value - letter of credit	$ 22

Number of members on MWCC Executive Committee responsible for oveseeing the affairs of MWCC.

No definition available.

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- Definition

Face (par) amount of debt instrument at time of issuance.

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- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

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- Definition

Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

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- Definition

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.

+ References

No definition available.

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- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

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