Employee Share-Based Incentives - Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Noncash compensation expense related to employee stock-based incentive plans
Cost of prior grants of RSUs, PSUs and SARs that are amortized over their applicable vesting periods	$ 1,241	$ 1,125	$ 1,046
Accrual of estimated costs of share-based awards to be granted in future periods including those to full-career eligible employees	1,081	945	894
Total noncash compensation expense related to employee share-based incentive plans	2,322	$ 2,070	$ 1,940
Compensation cost related to unvested awards not charged to net income	$ 704
Weighted-average period for cost expected to be amortized into compensation expense	1 year 7 months 6 days