Contingent Liabilities - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended		12 Months Ended
	Apr. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007	Jun. 30, 2014
Commitments and Contingencies Disclosure [Line Items]
Standby letters of credit outstanding			$ 4,500,000,000						$ 4,400,000,000
Minimum securities lending related collateral percentage									100.00%
Possible loss in future periods in excess of accrual									130,000,000
Legal Settlement Charge			19,200,000
Gain on redemption of Visa common stock							167,900,000
Remaining Visa shares held by Northern Trust, original cost basis							0
Visa indemnified litigation benefit (charges) recorded				23,100,000	33,000,000	17,800,000	76,100,000	(150,000,000)
Fair value of contingent consideration			55,400,000
Settlement of contingent consideration	55,300,000	55,300,000
Indemnification Agreement
Commitments and Contingencies Disclosure [Line Items]
Collateralized securities loaned, subject to indemnification			82,700,000,000						94,700,000,000
Credit loss liability			$ 0						$ 0