Earnings Per Share (EPS) And Dividends (Dividend Payments On Common Stock) (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
Feb. 28, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share, Diluted [Line Items]
Dividend Payments on Common Stock, Per Share		$ 1.96	$ 1.88	$ 1.80
Dividend Payments on Common Stock		$ 991	$ 950	$ 910
Subsequent Event [Member]
Earnings Per Share, Diluted [Line Items]
Common stock dividends per share	$ 0.51

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

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-Name Accounting Standards Codification
-Topic 505
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Aggregate dividends declared during the period for each share of common stock outstanding.

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Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
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