This amount represents the components of net periodic benefit costs (benefits) (such as interest, expected return on plan assets, prior service cost amortization and actuarial gain/loss) that no longer will be included within operating expense after adoption of ASU No. 2017-07.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Significant Accounting Policies - New Accounting Pronouncements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
ASU 2016-01 Recognition and Measurement of Financial Assets and Financial Liabilities \| Maximum
New Accounting Pronouncements or Change in Accounting Principle
Approximate equity securities and cost method investments in aggregate	$ 75
ASU 2017-07 Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost
New Accounting Pronouncements or Change in Accounting Principle
Amount of net periodic benefit costs (benefits) that will no longer be included within operating expenses once ASU No. 2017-07 is adopted.	$ (129)	$ (195)	$ 34