Information Relating to the Consolidated Statement of Cash Flows (Details Textual) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Supplemental Cash Flow Elements [Abstract]
Net purchases of treasury shares			$ 751	$ 1
Stock repurchased during period (in shares)			6,300,000	0
Stock repurchased during period			$ 750
Dividends paid of common stock (in dollars per share)	$ 1.12	$ 1.08	$ 3.36	$ 3.24

Aggregate dividends paid during the period for each share of common stock outstanding.

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The cash outflow to reacquire common stock during the period.

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Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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