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	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings per share:
Net income available to common shareholders	$ 2,419	$ 2,118	$ 2,105
Less: Income allocated to participating securities	21	23	23
Net income allocated to common shareholders	2,398	2,095	2,082
Earnings per diluted share:
Net income available to common shareholders	2,419	2,118	2,105
Stock-based awards	0	0	0
Net income available to common shareholders plus assumed conversions	2,419	2,118	2,105
Less: Income allocated to participating securities	21	23	23
Net income allocated to common shareholders plus assumed conversions	$ 2,398	$ 2,095	$ 2,082
Earnings per share:
Net income allocated to common shareholders	710,433,611	673,346,168	728,289,200
Effect of dilutive securities:
Stock-based awards	10,000,000	12,000,000	13,000,000
Net income allocated to common shareholders	720,065,498	685,488,498	740,691,433
Earnings per share:
Earnings per share - basic	$ 3.38	$ 3.11	$ 2.86
Earnings per diluted share:
Earnings per share - diluted	$ 3.33	$ 3.06	$ 2.81