EPS (Calculation of Earnings Per Share and the Reconciliation of Earnings Per Share to Earnings Per Diluted Share) (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Earnings per share:
Net income (loss) available to common shareholders	$ 760	$ 686
Less: Income allocated to participating securities	8	8
Earnings per share - basic	752	678
Earnings per diluted share:
Net income available to common shareholders	760	686
Stock-based awards	0	0
Net income available to common shareholders plus assumed conversions	760	686
Less: Income allocated to participating securities	8	8
Net income allocated to common shareholders	$ 752	$ 678
Earnings per share:
Net income allocated to common shareholders	661,057,120	689,820,295
Effect of dilutive securities:
Stock-based awards	10,000,000	14,000,000
Net income allocated to common shareholders	670,685,025	704,100,936
Earnings per share:
Earnings per share - basic	$ 1.14	$ 0.98
Earnings per diluted share:
Earnings per share - diluted	$ 1.12	$ 0.96

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Adjustment amount for dilutive impact to reconcile net income available to common shareholders as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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Amount of undistributed earnings (loss) allocated to participating securities for the diluted earnings (loss) per share or per unit calculation under the two-class method.

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