Employee Stock-Based Incentives - Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Noncash compensation expense related to employee stock-based incentive plans
Cost of prior grants of RSUs and SARs that are amortized over their applicable vesting periods	$ 1,109	$ 1,371	$ 1,440
Accrual of estimated costs of stock-based awards to be granted in future periods including those to full-career eligible employees	878	819	779
Total noncash compensation expense related to employee stock-based incentive plans	1,987	$ 2,190	$ 2,219
Compensation cost related to unvested awards not charged to net income	$ 688
Weighted average period for cost expected to be amortized into compensation expense	10 months 24 days