Subsequent Events	6 Months Ended
Jun. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	15. Subsequent Event On July 31, 2019, we entered into a credit agreement with a syndicate of banks. This agreement (the “credit facility”) allows for the issuance of letters of credit and borrowing of up to $2.25 billion. The credit facility is unsecured and has a commitment termination date of July 31, 2024. Under the credit facility, we pay a fee of 0.875% per annum on issued syndicated letters of credit and a facility fee of 0.125% per annum on the aggregate commitment. These fees adjust automatically in the event of a change in our credit ratings. Effective as of July 31, 2019, the credit facility replaced our credit agreement dated as of June 30, 2016, and the commitments under that agreement have been terminated.

The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-URI http://asc.fasb.org/topic&trid=2122774

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